diff --git a/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntime.java b/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntime.java
index d9a31c41a..832a1203a 100644
--- a/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntime.java
+++ b/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntime.java
@@ -18,9 +18,8 @@ import reactor.core.publisher.Mono;
 
 import java.io.Closeable;
 import java.io.IOException;
-import java.util.Collections;
-import java.util.HashMap;
-import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * Contains methods to register actor types. Registering the types allows the
@@ -66,7 +65,7 @@ public class ActorRuntime implements Closeable {
   /**
    * Map of ActorType --> ActorManager.
    */
-  private final Map<String, ActorManager> actorManagers;
+  private final ConcurrentMap<String, ActorManager> actorManagers;
 
   /**
    * The default constructor. This should not be called directly.
@@ -100,7 +99,7 @@ public class ActorRuntime implements Closeable {
     }
 
     this.config = new ActorRuntimeConfig();
-    this.actorManagers = Collections.synchronizedMap(new HashMap<>());
+    this.actorManagers = new ConcurrentHashMap<>();
     this.daprClient = daprClient;
     this.channel = channel;
   }
@@ -138,7 +137,7 @@ public class ActorRuntime implements Closeable {
    * @throws IOException If cannot serialize config.
    */
   public byte[] serializeConfig() throws IOException {
-    return this.INTERNAL_SERIALIZER.serialize(this.config);
+    return INTERNAL_SERIALIZER.serialize(this.config);
   }
 
   /**
@@ -207,17 +206,18 @@ public class ActorRuntime implements Closeable {
 
     ActorTypeInformation<T> actorTypeInfo = ActorTypeInformation.create(clazz);
 
-    ActorRuntimeContext<T> context = new ActorRuntimeContext<>(
-          this,
-          objectSerializer,
-          actorFactory,
-          actorTypeInfo,
-          this.daprClient,
-          new DaprStateAsyncProvider(this.daprClient, stateSerializer));
-
-    // Create ActorManagers, override existing entry if registered again.
-    this.actorManagers.put(actorTypeInfo.getName(), new ActorManager<T>(context));
-    this.config.addRegisteredActorType(actorTypeInfo.getName());
+    // Create ActorManager, if not yet registered.
+    this.actorManagers.computeIfAbsent(actorTypeInfo.getName(), (k) -> {
+      ActorRuntimeContext<T> context = new ActorRuntimeContext<>(
+              this,
+              objectSerializer,
+              actorFactory,
+              actorTypeInfo,
+              this.daprClient,
+              new DaprStateAsyncProvider(this.daprClient, stateSerializer));
+      this.config.addRegisteredActorType(actorTypeInfo.getName());
+      return new ActorManager<T>(context);
+    });
   }
 
   /**
diff --git a/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntimeConfig.java b/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntimeConfig.java
index 2a88ebce6..e10f87fbe 100644
--- a/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntimeConfig.java
+++ b/sdk-actors/src/main/java/io/dapr/actors/runtime/ActorRuntimeConfig.java
@@ -6,24 +6,25 @@
 package io.dapr.actors.runtime;
 
 import java.time.Duration;
-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 /**
  * Represents the configuration for the Actor Runtime.
  */
 public class ActorRuntimeConfig {
 
-  private Collection<String> registeredActorTypes = new ArrayList<>();
+  private List<String> registeredActorTypes = new CopyOnWriteArrayList<>();
 
-  private Duration actorIdleTimeout;
+  private volatile Duration actorIdleTimeout;
 
-  private Duration actorScanInterval;
+  private volatile Duration actorScanInterval;
 
-  private Duration drainOngoingCallTimeout;
+  private volatile Duration drainOngoingCallTimeout;
 
-  private Boolean drainBalancedActors;
+  private volatile Boolean drainBalancedActors;
 
   /**
    * Instantiates a new config for the Actor Runtime.