diff --git a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessage.java b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessage.java
index 668a447dbf..ff62838e0b 100644
--- a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessage.java
+++ b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessage.java
@@ -18,6 +18,9 @@
 import com.google.api.pathtemplate.ValidationException;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.primitives.Doubles;
+import com.google.common.primitives.Ints;
+import com.google.common.primitives.Longs;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Descriptors.Descriptor;
 import com.google.protobuf.Descriptors.FieldDescriptor;
@@ -226,6 +229,12 @@ private static void fillField(
           protoMsg.setField(fieldDescriptor, (Boolean) val);
           return;
         }
+        if (val instanceof String
+            && ("true".equals(((String) val).toLowerCase())
+                || "false".equals(((String) val).toLowerCase()))) {
+          protoMsg.setField(fieldDescriptor, Boolean.parseBoolean((String) val));
+          return;
+        }
         break;
       case BYTES:
         if (fieldSchema != null) {
@@ -312,6 +321,13 @@ private static void fillField(
           protoMsg.setField(fieldDescriptor, (Long) val);
           return;
         }
+        if (val instanceof String) {
+          Long parsed = Longs.tryParse((String) val);
+          if (parsed != null) {
+            protoMsg.setField(fieldDescriptor, parsed);
+            return;
+          }
+        }
         break;
       case INT32:
         if (fieldSchema != null && fieldSchema.getType() == TableFieldSchema.Type.DATE) {
@@ -327,6 +343,13 @@ private static void fillField(
           protoMsg.setField(fieldDescriptor, (Integer) val);
           return;
         }
+        if (val instanceof String) {
+          Integer parsed = Ints.tryParse((String) val);
+          if (parsed != null) {
+            protoMsg.setField(fieldDescriptor, parsed);
+            return;
+          }
+        }
         break;
       case STRING:
         if (val instanceof String) {
@@ -339,6 +362,13 @@ private static void fillField(
           protoMsg.setField(fieldDescriptor, ((Number) val).doubleValue());
           return;
         }
+        if (val instanceof String) {
+          Double parsed = Doubles.tryParse((String) val);
+          if (parsed != null) {
+            protoMsg.setField(fieldDescriptor, parsed);
+            return;
+          }
+        }
         break;
       case MESSAGE:
         if (val instanceof JSONObject) {
@@ -400,6 +430,10 @@ private static void fillRepeatedField(
         case BOOL:
           if (val instanceof Boolean) {
             protoMsg.addRepeatedField(fieldDescriptor, (Boolean) val);
+          } else if (val instanceof String
+              && ("true".equals(((String) val).toLowerCase())
+                  || "false".equals(((String) val).toLowerCase()))) {
+            protoMsg.addRepeatedField(fieldDescriptor, Boolean.parseBoolean((String) val));
           } else {
             fail = true;
           }
@@ -491,6 +525,13 @@ private static void fillRepeatedField(
             protoMsg.addRepeatedField(fieldDescriptor, new Long((Integer) val));
           } else if (val instanceof Long) {
             protoMsg.addRepeatedField(fieldDescriptor, (Long) val);
+          } else if (val instanceof String) {
+            Long parsed = Longs.tryParse((String) val);
+            if (parsed != null) {
+              protoMsg.addRepeatedField(fieldDescriptor, parsed);
+            } else {
+              fail = true;
+            }
           } else {
             fail = true;
           }
@@ -507,6 +548,13 @@ private static void fillRepeatedField(
             }
           } else if (val instanceof Integer) {
             protoMsg.addRepeatedField(fieldDescriptor, (Integer) val);
+          } else if (val instanceof String) {
+            Integer parsed = Ints.tryParse((String) val);
+            if (parsed != null) {
+              protoMsg.addRepeatedField(fieldDescriptor, parsed);
+            } else {
+              fail = true;
+            }
           } else {
             fail = true;
           }
@@ -521,6 +569,13 @@ private static void fillRepeatedField(
         case DOUBLE:
           if (val instanceof Number) {
             protoMsg.addRepeatedField(fieldDescriptor, ((Number) val).doubleValue());
+          } else if (val instanceof String) {
+            Double parsed = Doubles.tryParse((String) val);
+            if (parsed != null) {
+              protoMsg.addRepeatedField(fieldDescriptor, parsed);
+            } else {
+              fail = true;
+            }
           } else {
             fail = true;
           }
diff --git a/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessageTest.java b/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessageTest.java
index 7b5c6bcfad..90ff40c090 100644
--- a/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessageTest.java
+++ b/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/JsonToProtoMessageTest.java
@@ -473,15 +473,29 @@ public void testDifferentNameCasing() throws Exception {
     assertEquals(expectedProto, protoMsg);
   }
 
+  @Test
+  public void testBool() throws Exception {
+    TestBool expectedProto =
+        TestBool.newBuilder().setBool(true).setUppercase(true).setLowercase(false).build();
+    JSONObject json = new JSONObject();
+    json.put("bool", true);
+    json.put("uppercase", "TRUE");
+    json.put("lowercase", "false");
+    DynamicMessage protoMsg =
+        JsonToProtoMessage.convertJsonToProtoMessage(TestBool.getDescriptor(), json);
+    assertEquals(expectedProto, protoMsg);
+  }
+
   @Test
   public void testInt64() throws Exception {
     TestInt64 expectedProto =
-        TestInt64.newBuilder().setByte(1).setShort(1).setInt(1).setLong(1).build();
+        TestInt64.newBuilder().setByte(1).setShort(1).setInt(1).setLong(1).setString(1).build();
     JSONObject json = new JSONObject();
     json.put("byte", (byte) 1);
     json.put("short", (short) 1);
     json.put("int", 1);
     json.put("long", 1L);
+    json.put("string", "1");
     DynamicMessage protoMsg =
         JsonToProtoMessage.convertJsonToProtoMessage(TestInt64.getDescriptor(), json);
     assertEquals(expectedProto, protoMsg);
@@ -489,11 +503,13 @@ public void testInt64() throws Exception {
 
   @Test
   public void testInt32() throws Exception {
-    TestInt32 expectedProto = TestInt32.newBuilder().setByte(1).setShort(1).setInt(1).build();
+    TestInt32 expectedProto =
+        TestInt32.newBuilder().setByte(1).setShort(1).setInt(1).setString(1).build();
     JSONObject json = new JSONObject();
     json.put("byte", (byte) 1);
     json.put("short", (short) 1);
     json.put("int", 1);
+    json.put("string", 1);
     DynamicMessage protoMsg =
         JsonToProtoMessage.convertJsonToProtoMessage(TestInt32.getDescriptor(), json);
     assertEquals(expectedProto, protoMsg);
@@ -625,6 +641,7 @@ public void testDouble() throws Exception {
             .setShort(6)
             .setInt(7)
             .setLong(8)
+            .setString(9.1)
             .build();
     JSONObject json = new JSONObject();
     json.put("double", 1.2);
@@ -633,6 +650,7 @@ public void testDouble() throws Exception {
     json.put("short", new Short((short) 6));
     json.put("int", 7);
     json.put("long", 8L);
+    json.put("string", "9.1");
     DynamicMessage protoMsg =
         JsonToProtoMessage.convertJsonToProtoMessage(TestDouble.getDescriptor(), json);
     assertEquals(expectedProto, protoMsg);
diff --git a/google-cloud-bigquerystorage/src/test/proto/jsonTest.proto b/google-cloud-bigquerystorage/src/test/proto/jsonTest.proto
index fc76467f81..6fea46f021 100644
--- a/google-cloud-bigquerystorage/src/test/proto/jsonTest.proto
+++ b/google-cloud-bigquerystorage/src/test/proto/jsonTest.proto
@@ -103,17 +103,25 @@ message RepeatedObject {
   repeated ComplexLvl2 test_repeated = 1;
 }
 
+message TestBool {
+  optional bool bool = 1;
+  optional bool lowercase = 2;
+  optional bool uppercase = 3;
+}
+
 message TestInt64 {
   optional int64 byte = 1;
   optional int64 short = 2;
   optional int64 int = 3;
   optional int64 long = 4;
+  optional int64 string = 5;
 }
 
 message TestInt32 {
   optional int32 byte = 1;
   optional int32 short = 2;
   optional int32 int = 3;
+  optional int32 string = 4;
 }
 
 message TestDouble {
@@ -123,6 +131,7 @@ message TestDouble {
   optional double short = 4;
   optional double int = 5;
   optional double long = 6;
+  optional double string = 7;
 }
 
 message TestDate {