diff --git a/backend/API/Jobs/MoonrakerPrinterSyncJob.cs b/backend/API/Jobs/MoonrakerPrinterSyncJob.cs
new file mode 100644
index 0000000..f227c36
--- /dev/null
+++ b/backend/API/Jobs/MoonrakerPrinterSyncJob.cs
@@ -0,0 +1,80 @@
+using Extrudex.Domain.Interfaces;
+using Extrudex.Infrastructure.Configuration;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace Extrudex.API.Jobs;
+
+/// <summary>
+/// Background service that periodically syncs Moonraker printer status
+/// and print job history into the Extrudex database. Runs as a hosted
+/// service and polls all active Moonraker printers on a configurable
+/// interval to update printer state and map completed print jobs
+/// to PrintJob and FilamentUsage entities.
+///
+/// Configuration is bound from the "MoonrakerPrinterSync" section in
+/// appsettings.json. Set Enabled=false to disable without removing
+/// the service registration.
+/// </summary>
+public class MoonrakerPrinterSyncJob : BackgroundService
+{
+    private readonly IMoonrakerPrinterSyncService _syncService;
+    private readonly MoonrakerPrinterSyncOptions _options;
+    private readonly ILogger<MoonrakerPrinterSyncJob> _logger;
+
+    /// <summary>
+    /// Creates a new MoonrakerPrinterSyncJob.
+    /// </summary>
+    /// <param name="syncService">The service that performs the actual sync logic.</param>
+    /// <param name="options">Configuration options for polling interval and timeouts.</param>
+    /// <param name="logger">Logger for diagnostic output.</param>
+    public MoonrakerPrinterSyncJob(
+        IMoonrakerPrinterSyncService syncService,
+        IOptions<MoonrakerPrinterSyncOptions> options,
+        ILogger<MoonrakerPrinterSyncJob> logger)
+    {
+        _syncService = syncService;
+        _options = options.Value;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        if (!_options.Enabled)
+        {
+            _logger.LogInformation("Moonraker printer sync job is disabled via configuration — exiting");
+            return;
+        }
+
+        _logger.LogInformation(
+            "Moonraker printer sync job starting — polling every {Interval}",
+            _options.PollingInterval);
+
+        // Delay briefly on startup to allow the web host to fully initialize
+        await Task.Delay(TimeSpan.FromSeconds(15), stoppingToken);
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                var syncedCount = await _syncService.SyncAllAsync(stoppingToken);
+
+                _logger.LogInformation(
+                    "Moonraker printer sync completed — {SyncedCount} printer(s) synced. Next sync in {Interval}",
+                    syncedCount, _options.PollingInterval);
+            }
+            catch (Exception ex) when (ex is not OperationCanceledException)
+            {
+                _logger.LogError(ex,
+                    "Error during Moonraker printer sync cycle — will retry in {Interval}",
+                    _options.PollingInterval);
+            }
+
+            await Task.Delay(_options.PollingInterval, stoppingToken);
+        }
+
+        _logger.LogInformation("Moonraker printer sync job shutting down");
+    }
+}
\ No newline at end of file
diff --git a/backend/Domain/Interfaces/IMoonrakerPrinterSyncService.cs b/backend/Domain/Interfaces/IMoonrakerPrinterSyncService.cs
new file mode 100644
index 0000000..bb89ff8
--- /dev/null
+++ b/backend/Domain/Interfaces/IMoonrakerPrinterSyncService.cs
@@ -0,0 +1,20 @@
+using Extrudex.Domain.DTOs.Moonraker;
+
+namespace Extrudex.Domain.Interfaces;
+
+/// <summary>
+/// Service interface for syncing Moonraker printer data into the Extrudex database.
+/// Handles periodic polling of printer status and mapping print job history
+/// to PrintJob and FilamentUsage entities.
+/// </summary>
+public interface IMoonrakerPrinterSyncService
+{
+    /// <summary>
+    /// Performs a single sync cycle: queries all active Moonraker printers,
+    /// fetches their current status and print job history, and persists
+    /// updates to the database.
+    /// </summary>
+    /// <param name="cancellationToken">Cancellation token for graceful shutdown.</param>
+    /// <returns>The number of printers successfully synced.</returns>
+    Task<int> SyncAllAsync(CancellationToken cancellationToken = default);
+}
\ No newline at end of file
diff --git a/backend/Infrastructure/Configuration/MoonrakerPrinterSyncOptions.cs b/backend/Infrastructure/Configuration/MoonrakerPrinterSyncOptions.cs
new file mode 100644
index 0000000..442048b
--- /dev/null
+++ b/backend/Infrastructure/Configuration/MoonrakerPrinterSyncOptions.cs
@@ -0,0 +1,41 @@
+namespace Extrudex.Infrastructure.Configuration;
+
+/// <summary>
+/// Configuration options for the MoonrakerPrinterSync background service.
+/// Bound from appsettings.json under the "MoonrakerPrinterSync" section.
+/// Controls polling interval, timeouts, and feature toggles for the
+/// printer status and print job mapping service.
+/// </summary>
+public class MoonrakerPrinterSyncOptions
+{
+    /// <summary>
+    /// The section name in appsettings.json where these options are bound.
+    /// </summary>
+    public const string SectionName = "MoonrakerPrinterSync";
+
+    /// <summary>
+    /// How often the background service polls Moonraker printers for status
+    /// and print job data. Default: 1 minute.
+    /// </summary>
+    public TimeSpan PollingInterval { get; set; } = TimeSpan.FromMinutes(1);
+
+    /// <summary>
+    /// Timeout for individual HTTP requests to a Moonraker printer.
+    /// Default: 15 seconds.
+    /// </summary>
+    public TimeSpan RequestTimeout { get; set; } = TimeSpan.FromSeconds(15);
+
+    /// <summary>
+    /// Whether the Moonraker printer sync service is enabled.
+    /// Set to false to disable without removing the service registration.
+    /// Default: true.
+    /// </summary>
+    public bool Enabled { get; set; } = true;
+
+    /// <summary>
+    /// Maximum number of print history items to fetch per printer per sync cycle.
+    /// Controls the batch size when syncing print jobs from Moonraker.
+    /// Default: 25.
+    /// </summary>
+    public int HistoryBatchSize { get; set; } = 25;
+}
\ No newline at end of file
diff --git a/backend/Infrastructure/Services/MoonrakerPrinterSyncService.cs b/backend/Infrastructure/Services/MoonrakerPrinterSyncService.cs
new file mode 100644
index 0000000..48c20a2
--- /dev/null
+++ b/backend/Infrastructure/Services/MoonrakerPrinterSyncService.cs
@@ -0,0 +1,320 @@
+using Extrudex.Domain.DTOs.Moonraker;
+using Extrudex.Domain.Entities;
+using Extrudex.Domain.Enums;
+using Extrudex.Domain.Interfaces;
+using Extrudex.Infrastructure.Configuration;
+using Extrudex.Infrastructure.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+
+namespace Extrudex.Infrastructure.Services;
+
+/// <summary>
+/// Service that syncs Moonraker printer status and print job history into the
+/// Extrudex database. Queries all active Moonraker printers, fetches their
+/// current operational state, and maps completed print jobs to PrintJob and
+/// FilamentUsage entities with derived gram calculations.
+/// </summary>
+public class MoonrakerPrinterSyncService : IMoonrakerPrinterSyncService
+{
+    private readonly ExtrudexDbContext _dbContext;
+    private readonly IMoonrakerClient _moonrakerClient;
+    private readonly ILogger<MoonrakerPrinterSyncService> _logger;
+
+    /// <summary>
+    /// Creates a new MoonrakerPrinterSyncService.
+    /// </summary>
+    /// <param name="dbContext">The EF Core database context for persisting updates.</param>
+    /// <param name="moonrakerClient">The Moonraker HTTP client for fetching printer data.</param>
+    /// <param name="logger">Logger for diagnostic output.</param>
+    public MoonrakerPrinterSyncService(
+        ExtrudexDbContext dbContext,
+        IMoonrakerClient moonrakerClient,
+        ILogger<MoonrakerPrinterSyncService> logger)
+    {
+        _dbContext = dbContext;
+        _moonrakerClient = moonrakerClient;
+        _logger = logger;
+    }
+
+    /// <inheritdoc />
+    public async Task<int> SyncAllAsync(CancellationToken cancellationToken = default)
+    {
+        _logger.LogInformation("Starting Moonraker printer sync cycle");
+
+        var printers = await _dbContext.Printers
+            .Where(p => p.IsActive && p.ConnectionType == ConnectionType.Moonraker)
+            .Include(p => p.AmsUnits)
+                .ThenInclude(u => u.Slots)
+                    .ThenInclude(s => s.Spool)
+                        .ThenInclude(s => s.MaterialBase)
+            .Include(p => p.PrintJobs)
+            .ToListAsync(cancellationToken);
+
+        if (printers.Count == 0)
+        {
+            _logger.LogInformation("No active Moonraker printers found — skipping sync");
+            return 0;
+        }
+
+        _logger.LogInformation("Found {PrinterCount} active Moonraker printer(s) to sync", printers.Count);
+
+        var syncedCount = 0;
+
+        foreach (var printer in printers)
+        {
+            try
+            {
+                await SyncPrinterAsync(printer, cancellationToken);
+                syncedCount++;
+            }
+            catch (Exception ex) when (ex is not OperationCanceledException)
+            {
+                _logger.LogError(ex,
+                    "Error syncing printer {PrinterName} ({Host}:{Port})",
+                    printer.Name, printer.HostnameOrIp, printer.Port);
+
+                // Mark printer as offline if we can't reach it
+                printer.Status = PrinterStatus.Offline;
+            }
+        }
+
+        await _dbContext.SaveChangesAsync(cancellationToken);
+
+        _logger.LogInformation(
+            "Moonraker printer sync cycle complete — {SyncedCount}/{TotalCount} printers synced",
+            syncedCount, printers.Count);
+
+        return syncedCount;
+    }
+
+    /// <summary>
+    /// Syncs a single Moonraker printer: updates its status, fetches print history,
+    /// and maps new print jobs to database entities.
+    /// </summary>
+    private async Task SyncPrinterAsync(Printer printer, CancellationToken cancellationToken)
+    {
+        // Step 1: Fetch printer status
+        var printerInfo = await _moonrakerClient.GetPrinterInfoAsync(
+            printer.HostnameOrIp, printer.Port, printer.ApiKey, cancellationToken);
+
+        var printStats = await _moonrakerClient.GetPrintStatsAsync(
+            printer.HostnameOrIp, printer.Port, printer.ApiKey, cancellationToken);
+
+        // Step 2: Update printer status
+        UpdatePrinterStatus(printer, printerInfo, printStats);
+        printer.LastSeenAt = DateTime.UtcNow;
+
+        _logger.LogDebug(
+            "Printer {PrinterName} status updated to {Status}",
+            printer.Name, printer.Status);
+
+        // Step 3: Fetch and map print job history
+        var history = await _moonrakerClient.GetPrintHistoryAsync(
+            printer.HostnameOrIp, printer.Port, printer.ApiKey,
+            limit: 25,
+            cancellationToken);
+
+        if (history.Items.Count == 0)
+        {
+            _logger.LogDebug("No print history returned for printer {PrinterName}", printer.Name);
+            return;
+        }
+
+        var newJobsCount = await MapPrintJobsAsync(printer, history.Items, cancellationToken);
+
+        if (newJobsCount > 0)
+        {
+            _logger.LogInformation(
+                "Mapped {NewJobsCount} new print job(s) from printer {PrinterName}",
+                newJobsCount, printer.Name);
+        }
+    }
+
+    /// <summary>
+    /// Updates the printer's operational status based on Moonraker telemetry.
+    /// Maps Klipper/Moonraker state strings to the PrinterStatus enum.
+    /// </summary>
+    private void UpdatePrinterStatus(
+        Printer printer,
+        MoonrakerPrinterInfo? printerInfo,
+        MoonrakerPrintStats? printStats)
+    {
+        // Prefer print_stats state — it's the most authoritative
+        if (printStats != null)
+        {
+            printer.Status = printStats.State.ToLowerInvariant() switch
+            {
+                "printing" => PrinterStatus.Printing,
+                "paused" => PrinterStatus.Paused,
+                "complete" => PrinterStatus.Idle,
+                "standby" => PrinterStatus.Idle,
+                "cancelled" => PrinterStatus.Idle,
+                "error" => PrinterStatus.Error,
+                _ => PrinterStatus.Idle
+            };
+            return;
+        }
+
+        // Fall back to printer_info state
+        if (printerInfo != null)
+        {
+            printer.Status = printerInfo.State.ToLowerInvariant() switch
+            {
+                "ready" => PrinterStatus.Idle,
+                "startup" => PrinterStatus.Idle,
+                "shutdown" => PrinterStatus.Offline,
+                "error" => PrinterStatus.Error,
+                "cancelled" => PrinterStatus.Idle,
+                _ => printer.Status // Preserve existing status if unknown
+            };
+        }
+    }
+
+    /// <summary>
+    /// Maps Moonraker print job history items to Extrudex PrintJob and FilamentUsage entities.
+    /// Only creates records for jobs not already tracked (by Moonraker JobId stored in GcodeFilePath).
+    /// </summary>
+    private async Task<int> MapPrintJobsAsync(
+        Printer printer,
+        List<MoonrakerPrintJob> historyItems,
+        CancellationToken cancellationToken)
+    {
+        // Build a set of already-tracked Moonraker JobIds for this printer
+        // We store the Moonraker JobId in the GcodeFilePath field with a "moonraker:" prefix
+        var trackedJobIds = await _dbContext.PrintJobs
+            .Where(pj => pj.PrinterId == printer.Id && pj.GcodeFilePath != null && pj.GcodeFilePath.StartsWith("moonraker:"))
+            .Select(pj => pj.GcodeFilePath!)
+            .ToListAsync(cancellationToken);
+
+        var trackedIdSet = new HashSet<string>(trackedJobIds);
+        var newJobsCount = 0;
+
+        // Find the default spool for this printer (first active spool in AMS, or first active spool overall)
+        var defaultSpool = FindDefaultSpool(printer);
+
+        foreach (var moonrakerJob in historyItems)
+        {
+            var jobIdKey = $"moonraker:{moonrakerJob.JobId}";
+
+            if (trackedIdSet.Contains(jobIdKey))
+            {
+                continue; // Already tracked — skip
+            }
+
+            // Only map completed, cancelled, or errored jobs (not in_progress)
+            // In-progress jobs will be captured on the next cycle once they finish
+            if (moonrakerJob.Status == "in_progress")
+            {
+                continue;
+            }
+
+            // Map Moonraker job status to JobStatus enum
+            var jobStatus = moonrakerJob.Status.ToLowerInvariant() switch
+            {
+                "completed" => JobStatus.Completed,
+                "cancelled" => JobStatus.Cancelled,
+                "error" => JobStatus.Failed,
+                _ => JobStatus.Completed
+            };
+
+            // Calculate derived grams if we have a spool and filament data
+            decimal gramsDerived = 0m;
+            decimal filamentDiameterMm = 1.75m;
+            decimal materialDensity = 1.24m; // PLA default
+
+            if (defaultSpool != null)
+            {
+                filamentDiameterMm = defaultSpool.FilamentDiameterMm;
+                materialDensity = defaultSpool.MaterialBase.DensityGperCm3;
+                gramsDerived = CalculateGrams(moonrakerJob.FilamentUsedMm, filamentDiameterMm, materialDensity);
+            }
+            else if (moonrakerJob.FilamentUsedMm > 0)
+            {
+                gramsDerived = CalculateGrams(moonrakerJob.FilamentUsedMm, 1.75m, 1.24m);
+                _logger.LogWarning(
+                    "No default spool found for printer {PrinterName} — using PLA defaults for grams derivation on job {JobId}",
+                    printer.Name, moonrakerJob.JobId);
+            }
+
+            var printJob = new PrintJob
+            {
+                PrinterId = printer.Id,
+                SpoolId = defaultSpool?.Id ?? Guid.Empty,
+                PrintName = moonrakerJob.Filename,
+                GcodeFilePath = jobIdKey,
+                MmExtruded = moonrakerJob.FilamentUsedMm,
+                GramsDerived = gramsDerived,
+                StartedAt = moonrakerJob.StartTime,
+                CompletedAt = moonrakerJob.EndTime,
+                Status = jobStatus,
+                DataSource = DataSource.Moonraker,
+                FilamentDiameterAtPrintMm = filamentDiameterMm,
+                MaterialDensityAtPrint = materialDensity,
+                Notes = $"Auto-imported from Moonraker (JobId: {moonrakerJob.JobId})"
+            };
+
+            _dbContext.PrintJobs.Add(printJob);
+
+            // Create a FilamentUsage record if filament was consumed
+            if (moonrakerJob.FilamentUsedMm > 0 && defaultSpool != null)
+            {
+                var usage = new FilamentUsage
+                {
+                    PrintJob = printJob,
+                    SpoolId = defaultSpool.Id,
+                    PrinterId = printer.Id,
+                    GramsUsed = gramsDerived,
+                    MmExtruded = moonrakerJob.FilamentUsedMm,
+                    RecordedAt = DateTime.UtcNow,
+                    Notes = $"Auto-imported from Moonraker history (JobId: {moonrakerJob.JobId})"
+                };
+
+                _dbContext.FilamentUsages.Add(usage);
+            }
+
+            newJobsCount++;
+            trackedIdSet.Add(jobIdKey); // Prevent duplicates within this batch
+        }
+
+        return newJobsCount;
+    }
+
+    /// <summary>
+    /// Finds the default spool for a printer. Returns the first spool loaded
+    /// in an AMS slot, or null if no spool is available.
+    /// </summary>
+    private static Spool? FindDefaultSpool(Printer printer)
+    {
+        // Prefer the first active spool in an AMS slot
+        foreach (var amsUnit in printer.AmsUnits)
+        {
+            foreach (var slot in amsUnit.Slots)
+            {
+                if (slot.Spool != null && slot.Spool.IsActive && !slot.Spool.IsArchived)
+                {
+                    return slot.Spool;
+                }
+            }
+        }
+
+        return null;
+    }
+
+    /// <summary>
+    /// Calculates derived grams from millimeters extruded using the standard formula:
+    /// grams = mm_extruded × cross_section_area × material_density
+    /// where cross_section_area = π × (diameter / 2)²
+    /// </summary>
+    private static decimal CalculateGrams(decimal mmExtruded, decimal diameterMm, decimal densityGperCm3)
+    {
+        if (mmExtruded <= 0) return 0m;
+
+        var radiusCm = (double)diameterMm / 2.0 / 10.0; // mm to cm
+        var crossSectionAreaCm2 = Math.PI * radiusCm * radiusCm;
+        var mmToCm = (double)mmExtruded / 10.0;
+
+        var grams = mmToCm * crossSectionAreaCm2 * (double)densityGperCm3;
+        return (decimal)grams;
+    }
+}
\ No newline at end of file
diff --git a/backend/Program.cs b/backend/Program.cs
index c2bdcc9..c3ac2a1 100644
--- a/backend/Program.cs
+++ b/backend/Program.cs
@@ -92,6 +92,12 @@ builder.Services.AddHttpClient<IMoonrakerClient, MoonrakerClient>(client =>
 builder.Services.AddScoped<IFilamentUsageSyncService, FilamentUsageSyncService>();
 builder.Services.AddHostedService<FilamentUsageSyncJob>();
 
+// ── Moonraker Printer Sync (Background Service) ──────────
+builder.Services.Configure<MoonrakerPrinterSyncOptions>(
+    builder.Configuration.GetSection(MoonrakerPrinterSyncOptions.SectionName));
+builder.Services.AddScoped<IMoonrakerPrinterSyncService, MoonrakerPrinterSyncService>();
+builder.Services.AddHostedService<MoonrakerPrinterSyncJob>();
+
 // ── Health Checks ───────────────────────────────────────────
 builder.Services.AddHealthChecks()
     .AddNpgSql(connectionString);
diff --git a/backend/appsettings.json b/backend/appsettings.json
index e5c747f..d35bd81 100644
--- a/backend/appsettings.json
+++ b/backend/appsettings.json
@@ -14,5 +14,11 @@
     "PollingInterval": "00:05:00",
     "RequestTimeout": "00:00:30",
     "Enabled": true
+  },
+  "MoonrakerPrinterSync": {
+    "PollingInterval": "00:01:00",
+    "RequestTimeout": "00:00:15",
+    "Enabled": true,
+    "HistoryBatchSize": 25
   }
 }
\ No newline at end of file