diff --git a/spring-web/src/main/java/org/springframework/http/codec/json/Jackson2CodecSupport.java b/spring-web/src/main/java/org/springframework/http/codec/json/Jackson2CodecSupport.java
index 7292c4ca7f..ac19c4feff 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/json/Jackson2CodecSupport.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/json/Jackson2CodecSupport.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -75,11 +75,14 @@ public abstract class Jackson2CodecSupport {
 	private static final String JSON_VIEW_HINT_ERROR =
 			"@JsonView only supported for write hints with exactly 1 class argument: ";
 
-	private static final List<MimeType> DEFAULT_MIME_TYPES = List.of(
+	private static final List<MimeType> defaultMimeTypes = List.of(
 			MediaType.APPLICATION_JSON,
 			new MediaType("application", "*+json"),
 			MediaType.APPLICATION_NDJSON);
 
+	private static final List<MimeType> problemDetailMimeTypes =
+			Collections.singletonList(MediaType.APPLICATION_PROBLEM_JSON);
+
 
 	protected final Log logger = HttpLogging.forLogName(getClass());
 
@@ -90,8 +93,6 @@ public abstract class Jackson2CodecSupport {
 
 	private final List<MimeType> mimeTypes;
 
-	private final List<MimeType> problemDetailMimeTypes;
-
 
 	/**
 	 * Constructor with a Jackson {@link ObjectMapper} to use.
@@ -99,15 +100,7 @@ public abstract class Jackson2CodecSupport {
 	protected Jackson2CodecSupport(ObjectMapper objectMapper, MimeType... mimeTypes) {
 		Assert.notNull(objectMapper, "ObjectMapper must not be null");
 		this.defaultObjectMapper = objectMapper;
-		this.mimeTypes = (!ObjectUtils.isEmpty(mimeTypes) ? List.of(mimeTypes) : DEFAULT_MIME_TYPES);
-		this.problemDetailMimeTypes = initProblemDetailMediaTypes(this.mimeTypes);
-	}
-
-	private static List<MimeType> initProblemDetailMediaTypes(List<MimeType> supportedMimeTypes) {
-		List<MimeType> mimeTypes = new ArrayList<>();
-		mimeTypes.add(MediaType.APPLICATION_PROBLEM_JSON);
-		mimeTypes.addAll(supportedMimeTypes);
-		return Collections.unmodifiableList(mimeTypes);
+		this.mimeTypes = (!ObjectUtils.isEmpty(mimeTypes) ? List.of(mimeTypes) : defaultMimeTypes);
 	}
 
 
@@ -193,7 +186,7 @@ public abstract class Jackson2CodecSupport {
 		if (!CollectionUtils.isEmpty(result)) {
 			return result;
 		}
-		return (ProblemDetail.class.isAssignableFrom(elementClass) ? this.problemDetailMimeTypes : getMimeTypes());
+		return (ProblemDetail.class.isAssignableFrom(elementClass) ? problemDetailMimeTypes : getMimeTypes());
 	}
 
 	protected boolean supportsMimeType(@Nullable MimeType mimeType) {
diff --git a/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java b/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
index 595e70a323..a380f0171a 100644
--- a/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
+++ b/spring-web/src/main/java/org/springframework/http/converter/json/AbstractJackson2HttpMessageConverter.java
@@ -91,8 +91,9 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 		ENCODINGS.put("US-ASCII", JsonEncoding.UTF8);
 	}
 
+	private static final List<MediaType> problemDetailMediaTypes =
+			Collections.singletonList(MediaType.APPLICATION_PROBLEM_JSON);
 
-	private List<MediaType> problemDetailMediaTypes = Collections.singletonList(MediaType.APPLICATION_PROBLEM_JSON);
 
 	protected ObjectMapper defaultObjectMapper;
 
@@ -126,17 +127,9 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 
 	@Override
 	public void setSupportedMediaTypes(List<MediaType> supportedMediaTypes) {
-		this.problemDetailMediaTypes = initProblemDetailMediaTypes(supportedMediaTypes);
 		super.setSupportedMediaTypes(supportedMediaTypes);
 	}
 
-	private List<MediaType> initProblemDetailMediaTypes(List<MediaType> supportedMediaTypes) {
-		List<MediaType> mediaTypes = new ArrayList<>();
-		mediaTypes.add(MediaType.APPLICATION_PROBLEM_JSON);
-		mediaTypes.addAll(supportedMediaTypes);
-		return Collections.unmodifiableList(mediaTypes);
-	}
-
 	/**
 	 * Configure the main {@code ObjectMapper} to use for Object conversion.
 	 * If not set, a default {@link ObjectMapper} instance is created.
@@ -216,8 +209,7 @@ public abstract class AbstractJackson2HttpMessageConverter extends AbstractGener
 		if (!CollectionUtils.isEmpty(result)) {
 			return result;
 		}
-		return (ProblemDetail.class.isAssignableFrom(clazz) ?
-				this.problemDetailMediaTypes : getSupportedMediaTypes());
+		return (ProblemDetail.class.isAssignableFrom(clazz) ? problemDetailMediaTypes : getSupportedMediaTypes());
 	}
 
 	private Map<Class<?>, Map<MediaType, ObjectMapper>> getObjectMapperRegistrations() {
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java
index 79ecdb84dc..6cd9596a04 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -127,7 +127,11 @@ public class ResponseBodyResultHandlerTests {
 
 		// JSON requested
 		exchange = MockServerWebExchange.from(get("/path").accept(MediaType.APPLICATION_JSON));
-		testProblemDetailMediaType(exchange, MediaType.APPLICATION_JSON);
+		testProblemDetailMediaType(exchange, MediaType.APPLICATION_PROBLEM_JSON);
+
+		// JSON & Problem Detail requested (gh-29588)
+		exchange = MockServerWebExchange.from(get("/path").accept(MediaType.APPLICATION_JSON, MediaType.APPLICATION_PROBLEM_JSON));
+		testProblemDetailMediaType(exchange, MediaType.APPLICATION_PROBLEM_JSON);
 
 		// No match fallback
 		exchange = MockServerWebExchange.from(get("/path").accept(MediaType.APPLICATION_PDF));
diff --git a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java
index e7018c11e1..8b151228f8 100644
--- a/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java
+++ b/spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2022 the original author or authors.
+ * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -403,7 +403,13 @@ public class RequestResponseBodyMethodProcessorTests {
 	@Test
 	void problemDetailWhenJsonRequested() throws Exception {
 		this.servletRequest.addHeader("Accept", MediaType.APPLICATION_JSON_VALUE);
-		testProblemDetailMediaType(MediaType.APPLICATION_JSON_VALUE);
+		testProblemDetailMediaType(MediaType.APPLICATION_PROBLEM_JSON_VALUE);
+	}
+
+	@Test // gh-29588
+	void problemDetailWhenJsonAndProblemJsonRequested() throws Exception {
+		this.servletRequest.addHeader("Accept", MediaType.APPLICATION_JSON_VALUE + "," + MediaType.APPLICATION_PROBLEM_JSON_VALUE);
+		testProblemDetailMediaType(MediaType.APPLICATION_PROBLEM_JSON_VALUE);
 	}
 
 	@Test