diff --git a/src/components/marker-chart/Canvas.tsx b/src/components/marker-chart/Canvas.tsx
index 491a81e5fb..3072813af4 100644
--- a/src/components/marker-chart/Canvas.tsx
+++ b/src/components/marker-chart/Canvas.tsx
@@ -58,7 +58,10 @@ import {
   getTextColor,
   isValidGraphColor,
 } from 'firefox-profiler/profile-logic/graph-color';
-import { getSchemaFromMarker } from 'firefox-profiler/profile-logic/marker-schema';
+import {
+  getSchemaFromMarker,
+  getMarkerFieldValue,
+} from 'firefox-profiler/profile-logic/marker-schema';
 import { getBottomBoxInfoForStackFrame } from 'firefox-profiler/profile-logic/bottom-box';
 
 import type {
@@ -203,7 +206,7 @@ class MarkerChartCanvasImpl extends React.PureComponent<Props> {
     strokeColor: string;
     textColor: string;
   } {
-    const { getMarker, markerSchemaByName } = this.props;
+    const { getMarker, markerSchemaByName, thread } = this.props;
     const marker = getMarker(markerIndex);
 
     let color: GraphColor | null = null;
@@ -211,17 +214,16 @@ class MarkerChartCanvasImpl extends React.PureComponent<Props> {
     // Try to get color from the marker schema's colorField
     const schema = getSchemaFromMarker(markerSchemaByName, marker.data);
 
-    if (
-      schema &&
-      schema.colorField &&
-      marker.data &&
-      typeof marker.data === 'object'
-    ) {
-      // Use type assertion to safely access dynamic property
-      const fieldValue = (marker.data as any)[schema.colorField];
+    if (schema && schema.colorField) {
+      const fieldValue = getMarkerFieldValue(
+        marker.data,
+        schema.colorField,
+        schema,
+        thread.stringTable
+      );
       // Validate that the field value is a valid GraphColor
       if (typeof fieldValue === 'string' && isValidGraphColor(fieldValue)) {
-        color = fieldValue as GraphColor;
+        color = fieldValue;
       }
     }
 
diff --git a/src/profile-logic/marker-schema.ts b/src/profile-logic/marker-schema.ts
index 014452278a..ff2e61d8bb 100644
--- a/src/profile-logic/marker-schema.ts
+++ b/src/profile-logic/marker-schema.ts
@@ -98,6 +98,42 @@ export function getSchemaFromMarker(
   return schemaName ? (markerSchemaByName[schemaName] ?? null) : null;
 }
 
+/**
+ * Returns the value of a marker payload field. For fields declared as
+ * `unique-string` / `flow-id` / `terminating-flow-id` in the schema, the
+ * string-table index is dereferenced. Other formats — and fields not declared
+ * in the schema, or callers passing no schema — return the raw payload value.
+ * Returns undefined if the field isn't present on the marker, or if a
+ * unique-string field's value isn't a valid index into the string table.
+ */
+export function getMarkerFieldValue(
+  markerData: MarkerPayload | null,
+  fieldKey: string,
+  markerSchema: MarkerSchema | null,
+  stringTable: StringTable
+): unknown {
+  if (!markerData) {
+    return undefined;
+  }
+  const value = (markerData as any)[fieldKey];
+  if (value === undefined || value === null) {
+    return undefined;
+  }
+  const field = markerSchema?.fields.find((f) => f.key === fieldKey);
+  if (
+    field &&
+    (field.format === 'unique-string' ||
+      field.format === 'flow-id' ||
+      field.format === 'terminating-flow-id')
+  ) {
+    if (typeof value !== 'number' || !stringTable.hasIndex(value)) {
+      return undefined;
+    }
+    return stringTable.getString(value);
+  }
+  return value;
+}
+
 // Matches ternary expressions inside marker labels, ie {marker.data.field ? 'truthy' : 'falsy'}
 const TERNARY_RE = /^\s*([\w.]+)\s*\?\s*'([^']*)'\s*:\s*'([^']*)'\s*$/;
 
@@ -633,34 +669,16 @@ export function markerPayloadMatchesSearch(
 
   // Check if fields match the search regular expression.
   for (const payloadField of markerSchema.fields) {
-    let value = (data as any)[payloadField.key];
-    if (value === undefined || value === null) {
-      // The value is missing, but this is OK, values are optional.
+    const value = getMarkerFieldValue(
+      data,
+      payloadField.key,
+      markerSchema,
+      stringTable
+    );
+    if (value === undefined || value === '') {
       continue;
     }
-
-    if (
-      payloadField.format === 'unique-string' ||
-      payloadField.format === 'flow-id' ||
-      payloadField.format === 'terminating-flow-id'
-    ) {
-      if (typeof value !== 'number') {
-        console.warn(
-          `In marker ${marker.name}, the key ${payloadField.key} has an invalid value "${value}" as a unique string, it isn't a number.`
-        );
-        continue;
-      }
-
-      if (!stringTable.hasIndex(value)) {
-        console.warn(
-          `In marker ${marker.name}, the key ${payloadField.key} has an invalid index "${value}" as a unique string, as it's missing from the string table.`
-        );
-        continue;
-      }
-      value = stringTable.getString(value);
-    }
-
-    if (value !== '' && testFun(value, payloadField.key)) {
+    if (testFun(String(value), payloadField.key)) {
       return true;
     }
   }
diff --git a/src/profile-query/formatters/marker-info.ts b/src/profile-query/formatters/marker-info.ts
index e013493f79..7192da5b5a 100644
--- a/src/profile-query/formatters/marker-info.ts
+++ b/src/profile-query/formatters/marker-info.ts
@@ -13,6 +13,7 @@ import { getThreadSelectors } from 'firefox-profiler/selectors/per-thread';
 import {
   formatFromMarkerSchema,
   getLabelGetter,
+  getMarkerFieldValue,
 } from 'firefox-profiler/profile-logic/marker-schema';
 import { changeMarkersSearchString } from '../../actions/profile-view';
 import type { Store } from '../../types/store';
@@ -307,24 +308,16 @@ function getGroupingValue(
     return categories[marker.category]?.name ?? 'Unknown';
   }
   // Field-based grouping
-  const fieldValue = (marker.data as any)?.[key.field];
-  if (fieldValue === undefined || fieldValue === null) {
+  const schema = marker.data ? markerSchemaByName[marker.data.type] : null;
+  const fieldValue = getMarkerFieldValue(
+    marker.data,
+    key.field,
+    schema,
+    stringTable
+  );
+  if (fieldValue === undefined) {
     return '(no value)';
   }
-  // For fields whose format stores a string-table index (unique-string /
-  // flow-id / terminating-flow-id), resolve to the interned string so groups
-  // show "Error" / "click" / ... instead of integer indices.
-  const schema = marker.data ? markerSchemaByName[marker.data.type] : undefined;
-  const field = schema?.fields.find((f) => f.key === key.field);
-  if (
-    field &&
-    (field.format === 'unique-string' ||
-      field.format === 'flow-id' ||
-      field.format === 'terminating-flow-id') &&
-    typeof fieldValue === 'number'
-  ) {
-    return stringTable.getString(fieldValue, '(empty)');
-  }
   return String(fieldValue);
 }
 
diff --git a/src/test/components/MarkerChart.test.tsx b/src/test/components/MarkerChart.test.tsx
index d789a8f5e6..139a804af0 100644
--- a/src/test/components/MarkerChart.test.tsx
+++ b/src/test/components/MarkerChart.test.tsx
@@ -15,6 +15,7 @@ import {
   fireEvent,
   act,
 } from 'firefox-profiler/test/fixtures/testing-library';
+import { StringTable } from '../../utils/string-table';
 import { changeMarkersSearchString } from '../../actions/profile-view';
 import {
   TIMELINE_MARGIN_LEFT,
@@ -800,7 +801,10 @@ describe('MarkerChart', function () {
   });
 
   describe('Colored markers', () => {
-    function setupColoredMarkerTest(markers: TestDefinedMarker[]) {
+    function setupColoredMarkerTest(
+      markers: TestDefinedMarker[],
+      colorFieldFormat: 'string' | 'unique-string' = 'string'
+    ) {
       const profile = getProfileWithMarkers(markers);
 
       // Add marker schema with colorField to the profile
@@ -813,7 +817,7 @@ describe('MarkerChart', function () {
             {
               key: 'statusColor',
               label: 'Color',
-              format: 'string',
+              format: colorFieldFormat,
               hidden: true,
             },
           ],
@@ -821,6 +825,24 @@ describe('MarkerChart', function () {
         },
       ];
 
+      // getProfileWithMarkers only auto-interns unique-string fields for
+      // marker types in the default fixtures schema. The 'Test' schema is
+      // installed afterwards, so for unique-string we replace each
+      // statusColor value with its string-table index by hand.
+      if (colorFieldFormat === 'unique-string') {
+        const stringTable = StringTable.withBackingArray(
+          profile.shared.stringArray
+        );
+        for (const thread of profile.threads) {
+          for (let i = 0; i < thread.markers.length; i++) {
+            const data: any = thread.markers.data[i];
+            if (data && typeof data.statusColor === 'string') {
+              data.statusColor = stringTable.indexForString(data.statusColor);
+            }
+          }
+        }
+      }
+
       const { flushRafCalls } = setupWithProfile(profile);
       flushRafCalls();
       const drawLog = flushDrawLog();
@@ -879,6 +901,41 @@ describe('MarkerChart', function () {
       );
     });
 
+    it('renders markers with colors from a unique-string colorField', () => {
+      const markersWithColors: TestDefinedMarker[] = [
+        [
+          'Green Test',
+          0,
+          5,
+          {
+            type: 'Test',
+            status: 'success',
+            statusColor: 'green',
+          },
+        ],
+        [
+          'Red Test',
+          6,
+          10,
+          {
+            type: 'Test',
+            status: 'failure',
+            statusColor: 'red',
+          },
+        ],
+      ];
+
+      const fillColors = setupColoredMarkerTest(
+        markersWithColors,
+        'unique-string'
+      );
+
+      expect(fillColors).toEqual(
+        expect.arrayContaining([getFillColor('green'), getFillColor('red')])
+      );
+      expect(fillColors).not.toContain(DEFAULT_FILL_COLOR);
+    });
+
     it('falls back to default blue for markers without color data', () => {
       const markersWithoutColors: TestDefinedMarker[] = [
         [