diff --git a/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/src/connection/SupersetClientClass.ts b/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/src/connection/SupersetClientClass.ts
index 91fca25dde41a..a860d7bd6ea2a 100644
--- a/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/src/connection/SupersetClientClass.ts
+++ b/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/src/connection/SupersetClientClass.ts
@@ -74,7 +74,7 @@ export default class SupersetClientClass {
     this.baseUrl = url.href.replace(/\/+$/, ''); // always strip trailing slash
     this.host = url.host;
     this.protocol = url.protocol as Protocol;
-    this.headers = { ...headers };
+    this.headers = { Accept: 'application/json', ...headers }; // defaulting accept to json
     this.mode = mode;
     this.timeout = timeout;
     this.credentials = credentials;
diff --git a/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/test/connection/SupersetClient.test.ts b/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/test/connection/SupersetClient.test.ts
index cbe67b1508fcb..79596d428ca2b 100644
--- a/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/test/connection/SupersetClient.test.ts
+++ b/superset-frontend/temporary_superset_ui/superset-ui/packages/superset-ui-core/test/connection/SupersetClient.test.ts
@@ -53,7 +53,7 @@ describe('SupersetClient', () => {
 
   // this also tests that the ^above doesn't throw if configure is called appropriately
   it('calls appropriate SupersetClient methods when configured', async () => {
-    expect.assertions(10);
+    expect.assertions(15);
     const mockGetUrl = '/mock/get/url';
     const mockPostUrl = '/mock/post/url';
     const mockRequestUrl = '/mock/request/url';
@@ -90,6 +90,16 @@ describe('SupersetClient', () => {
     await SupersetClient.delete({ url: mockDeleteUrl });
     await SupersetClient.put({ url: mockPutUrl });
     await SupersetClient.request({ url: mockRequestUrl });
+
+    // Make sure network calls have  Accept: 'application/json' in headers
+    const networkCalls = [mockGetUrl, mockPostUrl, mockRequestUrl, mockPutUrl, mockDeleteUrl];
+    networkCalls.map((url: string) =>
+      expect(fetchMock.calls(url)[0][1]?.headers).toStrictEqual({
+        Accept: 'application/json',
+        'X-CSRFToken': '',
+      }),
+    );
+
     SupersetClient.isAuthenticated();
     await SupersetClient.reAuthenticate();