diff --git a/core/src/main/java/io/grpc/internal/JsonUtil.java b/core/src/main/java/io/grpc/internal/JsonUtil.java
index 6c9274702b6..cce3725beca 100644
--- a/core/src/main/java/io/grpc/internal/JsonUtil.java
+++ b/core/src/main/java/io/grpc/internal/JsonUtil.java
@@ -106,8 +106,8 @@ public static Double getNumberAsDouble(Map<String, ?> obj, String key) {
       return null;
     }
     Object value = obj.get(key);
-    if (value instanceof Double) {
-      return (Double) value;
+    if (value instanceof Number) {
+      return ((Number) value).doubleValue();
     }
     if (value instanceof String) {
       try {
@@ -132,8 +132,8 @@ public static Float getNumberAsFloat(Map<String, ?> obj, String key) {
       return null;
     }
     Object value = obj.get(key);
-    if (value instanceof Float) {
-      return (Float) value;
+    if (value instanceof Number) {
+      return ((Number) value).floatValue();
     }
     if (value instanceof String) {
       try {
@@ -159,11 +159,12 @@ public static Integer getNumberAsInteger(Map<String, ?> obj, String key) {
       return null;
     }
     Object value = obj.get(key);
-    if (value instanceof Double) {
-      Double d = (Double) value;
-      int i = d.intValue();
+    if (value instanceof Number) {
+      Number n = (Number) value;
+      double d = n.doubleValue();
+      int i = n.intValue();
       if (i != d) {
-        throw new ClassCastException("Number expected to be integer: " + d);
+        throw new ClassCastException("Number expected to be integer: " + n);
       }
       return i;
     }
@@ -190,11 +191,12 @@ public static Long getNumberAsLong(Map<String, ?> obj, String key) {
       return null;
     }
     Object value = obj.get(key);
-    if (value instanceof Double) {
-      Double d = (Double) value;
-      long l = d.longValue();
+    if (value instanceof Number) {
+      Number n = (Number) value;
+      double d = n.doubleValue();
+      long l = n.longValue();
       if (l != d) {
-        throw new ClassCastException("Number expected to be long: " + d);
+        throw new ClassCastException("Number expected to be long: " + n);
       }
       return l;
     }
diff --git a/core/src/main/java/io/grpc/internal/ManagedChannelImplBuilder.java b/core/src/main/java/io/grpc/internal/ManagedChannelImplBuilder.java
index 128c929ec0e..5224298984d 100644
--- a/core/src/main/java/io/grpc/internal/ManagedChannelImplBuilder.java
+++ b/core/src/main/java/io/grpc/internal/ManagedChannelImplBuilder.java
@@ -582,7 +582,7 @@ public ManagedChannelImplBuilder defaultServiceConfig(@Nullable Map<String, ?> s
         parsedMap.put(key, checkListEntryTypes((List<?>) value));
       } else if (value instanceof String) {
         parsedMap.put(key, value);
-      } else if (value instanceof Double) {
+      } else if (value instanceof Number) {
         parsedMap.put(key, value);
       } else if (value instanceof Boolean) {
         parsedMap.put(key, value);
@@ -606,7 +606,7 @@ private static List<?> checkListEntryTypes(List<?> list) {
         parsedList.add(checkListEntryTypes((List<?>) value));
       } else if (value instanceof String) {
         parsedList.add(value);
-      } else if (value instanceof Double) {
+      } else if (value instanceof Number) {
         parsedList.add(value);
       } else if (value instanceof Boolean) {
         parsedList.add(value);
diff --git a/core/src/test/java/io/grpc/internal/ManagedChannelImplBuilderTest.java b/core/src/test/java/io/grpc/internal/ManagedChannelImplBuilderTest.java
index b0939239477..a34b4debb19 100644
--- a/core/src/test/java/io/grpc/internal/ManagedChannelImplBuilderTest.java
+++ b/core/src/test/java/io/grpc/internal/ManagedChannelImplBuilderTest.java
@@ -737,7 +737,39 @@ public void defaultServiceConfig_intValue() {
     Map<String, Object> config = new HashMap<>();
     config.put("key", 3);
 
-    assertThrows(IllegalArgumentException.class, () -> builder.defaultServiceConfig(config));
+    builder.defaultServiceConfig(config);
+
+    assertThat(builder.defaultServiceConfig).containsExactlyEntriesIn(config);
+  }
+
+  @Test
+  public void defaultServiceConfig_longValue() {
+    Map<String, Object> config = new HashMap<>();
+    config.put("key", 3L);
+
+    builder.defaultServiceConfig(config);
+
+    assertThat(builder.defaultServiceConfig).containsExactlyEntriesIn(config);
+  }
+
+  @Test
+  public void defaultServiceConfig_list_intValue() {
+    Map<String, Object> config = new HashMap<>();
+    config.put("key", Collections.singletonList(3));
+
+    builder.defaultServiceConfig(config);
+
+    assertThat(builder.defaultServiceConfig).containsExactlyEntriesIn(config);
+  }
+
+  @Test
+  public void defaultServiceConfig_list_longValue() {
+    Map<String, Object> config = new HashMap<>();
+    config.put("key", Collections.singletonList(3L));
+
+    builder.defaultServiceConfig(config);
+
+    assertThat(builder.defaultServiceConfig).containsExactlyEntriesIn(config);
   }
 
   @Test