diff --git a/src/main/java/data_access/InMemoryGroupDataAccessObject.java b/src/main/java/data_access/InMemoryGroupDataAccessObject.java
index 63821fd..c8cc49c 100644
--- a/src/main/java/data_access/InMemoryGroupDataAccessObject.java
+++ b/src/main/java/data_access/InMemoryGroupDataAccessObject.java
@@ -8,6 +8,7 @@
 import use_case.login.LoginGroupsDataAccessInterface;
 import use_case.viewgrouptasks.ViewGroupTasksGroupDataAccessInterface;
 
+import java.security.SecureRandom;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -23,6 +24,9 @@ public class InMemoryGroupDataAccessObject implements
 
     private final Map<String, Group> groups = new HashMap<>();
     private String currentGroupID;
+    private static final String JOIN_CODE_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
+    private static final int JOIN_CODE_LENGTH = 6;
+    private final SecureRandom random = new SecureRandom();
 
     /**
      * Checks if the given groupCode exists.
@@ -53,6 +57,9 @@ public Group getGroup(String groupId) {
      */
     @Override
     public void save(Group group) {
+        if (group.getGroupID().isBlank()) {
+            group.setGroupId(generateUniqueJoinCode());
+        }
         groups.put(group.getGroupID(), group);
     }
 
@@ -89,4 +96,21 @@ public String getCurrentGroupID() {
     public void saveMasterSchedule(Group group) {
         groups.put(group.getGroupID(), group);
     }
+
+    private String generateUniqueJoinCode() {
+        String code;
+        do {
+            code = generateRandomJoinCode();
+        } while (groupCodeExists(code));
+        return code;
+    }
+
+    private String generateRandomJoinCode() {
+        StringBuilder sb = new StringBuilder(JOIN_CODE_LENGTH);
+        for (int i = 0; i < JOIN_CODE_LENGTH; i++) {
+            int idx = random.nextInt(JOIN_CODE_CHARS.length());
+            sb.append(JOIN_CODE_CHARS.charAt(idx));
+        }
+        return sb.toString();
+    }
 }
diff --git a/src/main/java/use_case/create_group/CreateGroupDataAccessInterface.java b/src/main/java/use_case/create_group/CreateGroupDataAccessInterface.java
index 91adfa8..907030b 100644
--- a/src/main/java/use_case/create_group/CreateGroupDataAccessInterface.java
+++ b/src/main/java/use_case/create_group/CreateGroupDataAccessInterface.java
@@ -23,7 +23,5 @@ public interface CreateGroupDataAccessInterface {
      * @param username the username whose group memberships are requested
      * @return a list of Group entities the user is a member of
      **/
-    default List<Group> getGroupsForUser(String username) {
-        return null;
-    }
+    List<Group> getGroupsForUser(String username);
 }
diff --git a/src/main/java/use_case/create_group/CreateGroupInteractor.java b/src/main/java/use_case/create_group/CreateGroupInteractor.java
index fa758bb..c953c18 100644
--- a/src/main/java/use_case/create_group/CreateGroupInteractor.java
+++ b/src/main/java/use_case/create_group/CreateGroupInteractor.java
@@ -57,6 +57,8 @@ public void execute(CreateGroupInputData createGroupInputData) {
                     group.getGroupID(), UserRole.MODERATOR, true);
 
             membershipDataAccessObject.save(membership);
+            groupCreator.addMembership(membership);
+            group.addMembership(membership);
             List<Group> newGroups = groupDataAccessObject.getGroupsForUser(groupCreator.getName());
             Map<String, String> newGroupHashMap = new HashMap<>();
             for (Group newGroup : newGroups) {
diff --git a/src/test/java/use_case/create_group/CreateGroupInteractorTest.java b/src/test/java/use_case/create_group/CreateGroupInteractorTest.java
index bc3f346..5711c7a 100644
--- a/src/test/java/use_case/create_group/CreateGroupInteractorTest.java
+++ b/src/test/java/use_case/create_group/CreateGroupInteractorTest.java
@@ -33,6 +33,8 @@ void successTest() {
             public void prepareSuccessView(CreateGroupOutputData outputData) {
                 assertEquals("Andrew's Group", outputData.getGroupName());
                 assertEquals(GroupType.PROJECT, outputData.getGroupType());
+                assertFalse(outputData.getGroupID().isBlank());
+                assertTrue(outputData.getGroups().containsKey(outputData.getGroupID()));
             }
 
             @Override
@@ -61,6 +63,7 @@ public void openCreateGroupModal() {
                         membershipFactory
                 );
 
+        interactor.openCreateGroupModal();
         interactor.execute(inputData);
     }
 
diff --git a/src/test/java/use_case/join_group/JoinGroupInteractorTest.java b/src/test/java/use_case/join_group/JoinGroupInteractorTest.java
index b8c5bd5..292cb91 100644
--- a/src/test/java/use_case/join_group/JoinGroupInteractorTest.java
+++ b/src/test/java/use_case/join_group/JoinGroupInteractorTest.java
@@ -45,6 +45,7 @@ void successValidGroupCodeTest() throws IOException {
         userDataAccess.save(myUser);
         userDataAccess.setCurrentUsername(myUser.getName());
 
+
         JoinGroupOutputBoundary successPresenter = new JoinGroupOutputBoundary() {
             @Override
             public void prepareSuccessView(JoinGroupOutputData outputData) {
@@ -75,6 +76,7 @@ void failureEmptyGroupCodeTest() throws IOException {
 
         User moderator = new User("moderator", "moderator@gmail.com", "pass");
         Group group = new Group("existing group to join", validCode, GroupType.STUDY);
+        group.setGroupId(validCode);
         Membership moderatorMembership = new Membership(moderator.getName(), group.getGroupID(), UserRole.MODERATOR, true);
 
         moderator.addMembership(moderatorMembership);