diff --git a/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommand.cs b/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommand.cs
index 63ff33a..989b85a 100644
--- a/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommand.cs
+++ b/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommand.cs
@@ -11,5 +11,5 @@ public sealed record CloseWorkflowCommand(
     byte? RejectionReasonId) : IRequest<CloseWorkflowResult>;
 
 public sealed record CloseWorkflowResult(
-    int ResultCode,
-    string ResultMessage);
+    int? Code,
+    string Message);
diff --git a/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommandHandler.cs b/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommandHandler.cs
index 9384e50..6a6f63e 100644
--- a/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommandHandler.cs
+++ b/src/core/DigitalData.TaskFlow.Application/Features/Workflows/Commands/CloseWorkflowCommandHandler.cs
@@ -1,16 +1,14 @@
+using DigitalData.TaskFlow.Application.Common.Exceptions;
 using DigitalData.TaskFlow.Application.Common.Interfaces;
 using MediatR;
 
 namespace DigitalData.TaskFlow.Application.Features.Workflows.Commands;
 
-public sealed class CloseWorkflowCommandHandler(IWorkflowRepository repo)
-    : IRequestHandler<CloseWorkflowCommand, CloseWorkflowResult>
+public sealed class CloseWorkflowCommandHandler(IWorkflowRepository Repo) : IRequestHandler<CloseWorkflowCommand, CloseWorkflowResult>
 {
-    public async Task<CloseWorkflowResult> Handle(
-        CloseWorkflowCommand request,
-        CancellationToken cancellationToken)
+    public async Task<CloseWorkflowResult> Handle(CloseWorkflowCommand request, CancellationToken cancellationToken)
     {
-        var procedureResult = await repo.CloseAsync(
+        var procedureResult = await Repo.CloseAsync(
             userId: request.WisagId,
             source: request.Source,
             processId: request.ProcessId,
@@ -19,14 +17,10 @@ public sealed class CloseWorkflowCommandHandler(IWorkflowRepository repo)
             rejectionReasonId: request.RejectionReasonId,
             cancellationToken: cancellationToken);
 
-        if (procedureResult?.Code is null)
-        {
-            throw new InvalidOperationException(
-                "Stored procedure returned an invalid close result.");
-        }
-
-        return new CloseWorkflowResult(
-            ResultCode: procedureResult.Code.Value,
-            ResultMessage: procedureResult.Result ?? string.Empty);
+        return procedureResult is null
+            ? throw new InvalidWorkflowPayloadException("Close workflow closing procedure returned no result.")
+            : new CloseWorkflowResult(
+                    Code: procedureResult.Code,
+                    Message: procedureResult.Result ?? string.Empty);
     }
 }
diff --git a/src/presentation/DigitalData.TaskFlow.API/Controllers/WorkflowsController.cs b/src/presentation/DigitalData.TaskFlow.API/Controllers/WorkflowsController.cs
index c204aed..d400f8f 100644
--- a/src/presentation/DigitalData.TaskFlow.API/Controllers/WorkflowsController.cs
+++ b/src/presentation/DigitalData.TaskFlow.API/Controllers/WorkflowsController.cs
@@ -1,3 +1,6 @@
+using DigitalData.TaskFlow.API.Models;
+using DigitalData.TaskFlow.Application.Common.Exceptions;
+using DigitalData.TaskFlow.Application.Features.Workflows.Commands;
 using DigitalData.TaskFlow.Application.Features.Workflows.Queries;
 using MediatR;
 using Microsoft.AspNetCore.Mvc;
@@ -29,18 +32,45 @@ public sealed class WorkflowsController(ISender sender) : ControllerBase
     }
 
     /// <summary>
-    /// 
+    /// Closes a workflow for a WISAG user identifier, source, and process identifier.
     /// </summary>
     /// <param name="wisagId"></param>
-    /// <param name="source"></param>
     /// <param name="processId"></param>
+    /// <param name="body"></param>
+    /// <param name="source"></param>
     /// <param name="cancellationToken"></param>
     /// <returns></returns>
-    /// <exception cref="NotImplementedException"></exception>
     [HttpPost("{wisagId:int}/{source}/{processId:long}/closing")]
-    [ProducesResponseType(StatusCodes.Status501NotImplemented)]
-    public Task<ActionResult<JsonElement>> CloseAsync([FromRoute] int wisagId, [FromRoute] string source, [FromRoute] long processId, CancellationToken cancellationToken)
+    [ProducesResponseType(StatusCodes.Status200OK)]
+    [ProducesResponseType(StatusCodes.Status400BadRequest)]
+    [ProducesResponseType(StatusCodes.Status404NotFound)]
+    [ProducesResponseType(StatusCodes.Status409Conflict)]
+    [ProducesResponseType(StatusCodes.Status500InternalServerError)]
+    public async Task<IActionResult> CloseAsync(
+        [FromRoute] int wisagId,
+        [FromRoute] long processId,
+        [FromBody] CloseWorkflowReqBody body,
+        [FromRoute] string source = "Ferdinand",
+        CancellationToken cancellationToken = default)
     {
-        throw new NotImplementedException();
+        var result = await sender.Send(
+            new CloseWorkflowCommand(
+                WisagId: wisagId,
+                Source: source,
+                ProcessId: processId,
+                ClosingMethodId: body.ClosingMethodId,
+                Comment: body.Comment,
+                RejectionReasonId: body.RejectionReasonId),
+            cancellationToken);
+
+        var metaResult = new CloseWorkflowReqResponse() { Meta = [result] };
+        return result.Code switch
+        {
+            0 => Ok(metaResult),
+            4 => BadRequest(metaResult),
+            6 => NotFound(metaResult),
+            7 => Conflict(metaResult),
+            _ => StatusCode(StatusCodes.Status500InternalServerError, metaResult)
+        };
     }
 }