diff --git a/src/plugins/data/public/search/search_source/normalize_sort_request.test.ts b/src/plugins/data/public/search/search_source/normalize_sort_request.test.ts
index d47aab80ee0bc..10004b87ca690 100644
--- a/src/plugins/data/public/search/search_source/normalize_sort_request.test.ts
+++ b/src/plugins/data/public/search/search_source/normalize_sort_request.test.ts
@@ -23,13 +23,23 @@ import { IIndexPattern } from '../..';
 
 describe('SearchSource#normalizeSortRequest', function () {
   const scriptedField = {
-    name: 'script string',
+    name: 'script number',
     type: 'number',
     scripted: true,
     sortable: true,
     script: 'foo',
     lang: 'painless',
   };
+  const stringScriptedField = {
+    ...scriptedField,
+    name: 'script string',
+    type: 'string',
+  };
+  const booleanScriptedField = {
+    ...scriptedField,
+    name: 'script boolean',
+    type: 'boolean',
+  };
   const murmurScriptedField = {
     ...scriptedField,
     sortable: false,
@@ -37,7 +47,7 @@ describe('SearchSource#normalizeSortRequest', function () {
     type: 'murmur3',
   };
   const indexPattern = {
-    fields: [scriptedField, murmurScriptedField],
+    fields: [scriptedField, stringScriptedField, booleanScriptedField, murmurScriptedField],
   } as IIndexPattern;
 
   it('should return an array', function () {
@@ -106,6 +116,54 @@ describe('SearchSource#normalizeSortRequest', function () {
     ]);
   });
 
+  it('should use script based sorting with string type', function () {
+    const result = normalizeSortRequest(
+      [
+        {
+          [stringScriptedField.name]: SortDirection.asc,
+        },
+      ],
+      indexPattern
+    );
+
+    expect(result).toEqual([
+      {
+        _script: {
+          script: {
+            source: stringScriptedField.script,
+            lang: stringScriptedField.lang,
+          },
+          type: 'string',
+          order: SortDirection.asc,
+        },
+      },
+    ]);
+  });
+
+  it('should use script based sorting with boolean type as string type', function () {
+    const result = normalizeSortRequest(
+      [
+        {
+          [booleanScriptedField.name]: SortDirection.asc,
+        },
+      ],
+      indexPattern
+    );
+
+    expect(result).toEqual([
+      {
+        _script: {
+          script: {
+            source: booleanScriptedField.script,
+            lang: booleanScriptedField.lang,
+          },
+          type: 'string',
+          order: SortDirection.asc,
+        },
+      },
+    ]);
+  });
+
   it('should use script based sorting only on sortable types', function () {
     const result = normalizeSortRequest(
       [
diff --git a/src/plugins/data/public/search/search_source/normalize_sort_request.ts b/src/plugins/data/public/search/search_source/normalize_sort_request.ts
index 9a0cf371ce81d..b00d28b38d670 100644
--- a/src/plugins/data/public/search/search_source/normalize_sort_request.ts
+++ b/src/plugins/data/public/search/search_source/normalize_sort_request.ts
@@ -69,7 +69,7 @@ function normalize(
 
 // The ES API only supports sort scripts of type 'number' and 'string'
 function castSortType(type: string) {
-  if (['number', 'string'].includes(type)) {
+  if (['number'].includes(type)) {
     return 'number';
   } else if (['string', 'boolean'].includes(type)) {
     return 'string';