diff --git a/extensions/jaxb/deployment/pom.xml b/extensions/jaxb/deployment/pom.xml
index 15589c3c49e5b..53d532adc436b 100644
--- a/extensions/jaxb/deployment/pom.xml
+++ b/extensions/jaxb/deployment/pom.xml
@@ -56,9 +56,6 @@
                                     <version>${project.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>
diff --git a/extensions/jaxb/deployment/src/main/java/io/quarkus/jaxb/deployment/JaxbProcessor.java b/extensions/jaxb/deployment/src/main/java/io/quarkus/jaxb/deployment/JaxbProcessor.java
index b08e753e7b3fa..aaf0c32bc958f 100644
--- a/extensions/jaxb/deployment/src/main/java/io/quarkus/jaxb/deployment/JaxbProcessor.java
+++ b/extensions/jaxb/deployment/src/main/java/io/quarkus/jaxb/deployment/JaxbProcessor.java
@@ -342,8 +342,8 @@ FilteredJaxbClassesToBeBoundBuildItem filterBoundClasses(
                 .forEach(builder::classNames);
 
         // remove classes that have been excluded by users
-        if (config.excludeClasses.isPresent()) {
-            builder.classNameExcludes(config.excludeClasses.get());
+        if (config.excludeClasses().isPresent()) {
+            builder.classNameExcludes(config.excludeClasses().get());
         }
         return builder.build();
     }
@@ -362,7 +362,7 @@ void bindClassesToJaxbContext(
                 .resolveBeans(Type.create(DotName.createSimple(JAXBContext.class), org.jboss.jandex.Type.Kind.CLASS));
         if (!beans.isEmpty()) {
             jaxbContextConfig.addClassesToBeBound(filteredClassesToBeBound.getClasses());
-            if (config.validateJaxbContext) {
+            if (config.validateJaxbContext()) {
                 validateJaxbContext(filteredClassesToBeBound, beanResolver, beans);
             }
         }
diff --git a/extensions/jaxb/runtime/pom.xml b/extensions/jaxb/runtime/pom.xml
index 3c6144fcbb637..17ad6ef0aede2 100644
--- a/extensions/jaxb/runtime/pom.xml
+++ b/extensions/jaxb/runtime/pom.xml
@@ -71,9 +71,6 @@
                                     <version>${project.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>
diff --git a/extensions/jaxb/runtime/src/main/java/io/quarkus/jaxb/runtime/JaxbConfig.java b/extensions/jaxb/runtime/src/main/java/io/quarkus/jaxb/runtime/JaxbConfig.java
index 10aee70162135..dc456f329460b 100644
--- a/extensions/jaxb/runtime/src/main/java/io/quarkus/jaxb/runtime/JaxbConfig.java
+++ b/extensions/jaxb/runtime/src/main/java/io/quarkus/jaxb/runtime/JaxbConfig.java
@@ -3,24 +3,25 @@
 import java.util.List;
 import java.util.Optional;
 
-import io.quarkus.runtime.annotations.ConfigItem;
 import io.quarkus.runtime.annotations.ConfigPhase;
 import io.quarkus.runtime.annotations.ConfigRoot;
+import io.smallrye.config.ConfigMapping;
+import io.smallrye.config.WithDefault;
 
-@ConfigRoot(phase = ConfigPhase.BUILD_AND_RUN_TIME_FIXED, name = "jaxb")
-public class JaxbConfig {
+@ConfigRoot(phase = ConfigPhase.BUILD_AND_RUN_TIME_FIXED)
+@ConfigMapping(prefix = "quarkus.jaxb")
+public interface JaxbConfig {
 
     /**
      * If enabled, it will validate the default JAXB context at build time.
      */
-    @ConfigItem(defaultValue = "false")
-    public boolean validateJaxbContext;
+    @WithDefault("false")
+    boolean validateJaxbContext();
 
     /**
      * Exclude classes to automatically be bound to the default JAXB context.
      * Values with suffix {@code .*}, i.e. {@code org.acme.*}, are considered packages and exclude all classes that are members
      * of these packages
      */
-    @ConfigItem
-    public Optional<List<String>> excludeClasses;
+    Optional<List<String>> excludeClasses();
 }