diff --git a/app/models/identity/joinable.rb b/app/models/identity/joinable.rb
index 52afb339a0..1d0c4cd05f 100644
--- a/app/models/identity/joinable.rb
+++ b/app/models/identity/joinable.rb
@@ -1,13 +1,33 @@
 module Identity::Joinable
   extend ActiveSupport::Concern
 
+  # Enables user reactivation when rejoining an account after deactivation.
+  #
+  # Relies on User#deactivate preserving the identity link (no `identity: nil`).
+  # When a deactivated user rejoins, find_or_create_by! finds their existing
+  # record and the reactivation block restores them to active status.
+  #
+  # Return value semantics for JoinCode#redeem_if:
+  #   - true:  new user created (increments usage count)
+  #   - false: existing user found (active or reactivated, no increment)
+
   def join(account, **attributes)
     attributes[:name] ||= email_address
 
     transaction do
-      account.users.find_or_create_by!(identity: self) do |user|
-        user.assign_attributes(attributes)
-      end.previously_new_record?
+      user = account.users.find_or_create_by!(identity: self) do |u|
+        u.assign_attributes(attributes)
+      end
+
+      # Reactivate if found but inactive. New users get board access via
+      # after_create_commit callback, but reactivated users need it manually
+      # since update! doesn't trigger create callbacks.
+      unless user.previously_new_record? || user.active?
+        user.update!(active: true)
+        user.send(:grant_access_to_boards)
+      end
+
+      user.previously_new_record?
     end
   end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index e16d70670a..dfbf462aa3 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -17,11 +17,9 @@ class User < ApplicationRecord
   has_many :exports, class_name: "Account::Export", dependent: :destroy
 
   def deactivate
-    transaction do
-      accesses.destroy_all
-      update! active: false, identity: nil
-      close_remote_connections
-    end
+    accesses.destroy_all
+    update! active: false
+    close_remote_connections
   end
 
   def setup?
diff --git a/test/controllers/join_codes_controller_test.rb b/test/controllers/join_codes_controller_test.rb
index 81a4ea6eae..95b3f353c7 100644
--- a/test/controllers/join_codes_controller_test.rb
+++ b/test/controllers/join_codes_controller_test.rb
@@ -55,6 +55,27 @@ class JoinCodesControllerTest < ActionDispatch::IntegrationTest
     assert_redirected_to landing_url(script_name: @account.slug)
   end
 
+  test "create for existing identity with deactivated user" do
+    identity = identities(:kevin)
+    user = users(:kevin)
+
+    sign_in_as :kevin
+
+    assert user.setup?, "Kevin should be setup for this test"
+    user.deactivate
+
+    assert_not user.reload.active?, "user should be inactive after deactivation"
+    assert_equal identity.id, user.identity_id, "identity link should be preserved after deactivation"
+
+    assert_no_difference -> { User.count } do
+      post join_path(code: @join_code.code, script_name: @account.slug), params: { email_address: identity.email_address }
+    end
+
+    user.reload
+    assert user.active?, "user should be reactivated after joining"
+    assert_redirected_to landing_url(script_name: @account.slug)
+  end
+
   test "create for signed-in identity without a user in the account redirects to verification" do
     identity = identities(:mike)
     sign_in_as :mike
diff --git a/test/models/identity/joinable_test.rb b/test/models/identity/joinable_test.rb
index 95ee0e04b6..03569e9297 100644
--- a/test/models/identity/joinable_test.rb
+++ b/test/models/identity/joinable_test.rb
@@ -34,4 +34,26 @@ class Identity::JoinableTest < ActiveSupport::TestCase
       assert_not result, "join should return false when user already exists"
     end
   end
+
+  test "join reactivates a deactivated user" do
+    identity = identities(:kevin)
+    account = accounts("37s")
+    user = users(:kevin)
+
+    user.stubs(:close_remote_connections)
+    user.deactivate
+
+    assert_not user.reload.active?, "user should be inactive after deactivation"
+    assert_empty user.accesses, "user should have no accesses after deactivation"
+    assert_equal identity.id, user.identity_id, "identity link should be preserved after deactivation"
+
+    assert_no_difference -> { User.count } do
+      result = identity.join(account)
+      assert_not result, "join should return false for reactivation"
+    end
+
+    user.reload
+    assert user.active?, "user should be active after reactivation"
+    assert user.accesses.any?, "user should have accesses restored after reactivation"
+  end
 end