diff --git a/db/docs/jira_connect_installations.yml b/db/docs/jira_connect_installations.yml
index f5c4bd7d8a2667bb48918edc2c983b4a3663d4ab..a245b15ad6acdc5aa756c104299c4d29ce2f26e7 100644
--- a/db/docs/jira_connect_installations.yml
+++ b/db/docs/jira_connect_installations.yml
@@ -8,5 +8,6 @@ description: GitLab for Jira Cloud app installation data, formerly Jira Connect
 introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/9593
 milestone: '11.9'
 gitlab_schema: gitlab_main_org
-sharding_key_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/560334
 table_size: small
+sharding_key:
+  organization_id: organizations
diff --git a/db/post_migrate/20250924101346_backfill_jira_connect_installations_organization_id.rb b/db/post_migrate/20250924101346_backfill_jira_connect_installations_organization_id.rb
new file mode 100644
index 0000000000000000000000000000000000000000..5afaa86747f4de5d498c94bb30f6473073c46cd0
--- /dev/null
+++ b/db/post_migrate/20250924101346_backfill_jira_connect_installations_organization_id.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+class BackfillJiraConnectInstallationsOrganizationId < Gitlab::Database::Migration[2.3]
+  milestone '18.5'
+  disable_ddl_transaction!
+  restrict_gitlab_migration gitlab_schema: :gitlab_main_org
+
+  BATCH_SIZE = 1000
+  DEFAULT_ORGANIZATION_ID = 1
+
+  def up
+    define_batchable_model('jira_connect_installations')
+      .where(organization_id: nil)
+      .each_batch(of: BATCH_SIZE) do |batch|
+      batch.update_all(organization_id: DEFAULT_ORGANIZATION_ID)
+    end
+  end
+
+  def down
+    # no-op
+  end
+end
diff --git a/db/post_migrate/20250924103022_validate_jira_connect_installations_not_null_constraint_on_organization_id.rb b/db/post_migrate/20250924103022_validate_jira_connect_installations_not_null_constraint_on_organization_id.rb
new file mode 100644
index 0000000000000000000000000000000000000000..4f09dc8dbd3761d7b14c855f86a8e46920ef894a
--- /dev/null
+++ b/db/post_migrate/20250924103022_validate_jira_connect_installations_not_null_constraint_on_organization_id.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+class ValidateJiraConnectInstallationsNotNullConstraintOnOrganizationId < Gitlab::Database::Migration[2.3]
+  milestone '18.5'
+  disable_ddl_transaction!
+
+  TABLE_NAME = :jira_connect_installations
+  COLUMN_NAME = :organization_id
+  CONSTRAINT_NAME = :check_dc0d039821
+
+  def up
+    validate_not_null_constraint :jira_connect_installations, :organization_id
+  end
+
+  def down
+    # no-op
+  end
+end
diff --git a/db/schema_migrations/20250924101346 b/db/schema_migrations/20250924101346
new file mode 100644
index 0000000000000000000000000000000000000000..34c444368bd3eab5e999565b8dcb5558d1eb86ec
--- /dev/null
+++ b/db/schema_migrations/20250924101346
@@ -0,0 +1 @@
+1ecd4544179e900e28c6c9b46db385709ffc7ab345971e762ed9af0298117454
\ No newline at end of file
diff --git a/db/schema_migrations/20250924103022 b/db/schema_migrations/20250924103022
new file mode 100644
index 0000000000000000000000000000000000000000..c8250baaed23238248e1ae10b8b43995a87ba873
--- /dev/null
+++ b/db/schema_migrations/20250924103022
@@ -0,0 +1 @@
+fca38d0a69134a7cf8222bb4e2723c9630f29fd5612b43228580bb0eb61528a5
\ No newline at end of file
diff --git a/db/structure.sql b/db/structure.sql
index 73340652aedb470b4445c2974b78903e3a5a1499..a3a5d76f2b64fda2daa9cf666f393e3874696b48 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -18565,7 +18565,8 @@ CREATE TABLE jira_connect_installations (
     base_url character varying,
     instance_url text,
     organization_id bigint,
-    CONSTRAINT check_4c6abed669 CHECK ((char_length(instance_url) <= 255))
+    CONSTRAINT check_4c6abed669 CHECK ((char_length(instance_url) <= 255)),
+    CONSTRAINT check_dc0d039821 CHECK ((organization_id IS NOT NULL))
 );
 
 CREATE SEQUENCE jira_connect_installations_id_seq
@@ -32836,9 +32837,6 @@ ALTER TABLE work_item_custom_statuses
 ALTER TABLE packages_packages
     ADD CONSTRAINT check_d6301aedeb CHECK ((char_length(status_message) <= 255)) NOT VALID;
 
-ALTER TABLE jira_connect_installations
-    ADD CONSTRAINT check_dc0d039821 CHECK ((organization_id IS NOT NULL)) NOT VALID;
-
 ALTER TABLE sprints
     ADD CONSTRAINT check_df3816aed7 CHECK ((due_date IS NOT NULL)) NOT VALID;
 
diff --git a/spec/migrations/backfill_jira_connect_installations_organization_id_spec.rb b/spec/migrations/backfill_jira_connect_installations_organization_id_spec.rb
new file mode 100644
index 0000000000000000000000000000000000000000..40cf41e9c5f6443dc77370a9cf7a08012b62ef51
--- /dev/null
+++ b/spec/migrations/backfill_jira_connect_installations_organization_id_spec.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+require_migration!
+
+RSpec.describe BackfillJiraConnectInstallationsOrganizationId, feature_category: :integrations do
+  let(:organizations) { table(:organizations) }
+  let(:installations) { table(:jira_connect_installations) }
+  let(:organization) { organizations.create!(id: 1, name: 'Default', path: 'default') }
+
+  let(:installation_without_organization) do
+    installations.create!(
+      client_key: 'foo',
+      base_url: 'https://example.com',
+      instance_url: 'https://example.com'
+    )
+  end
+
+  let(:another_installation_without_organization) do
+    installations.create!(
+      client_key: 'bar',
+      base_url: 'https://example.com',
+      instance_url: 'https://example.com'
+    )
+  end
+
+  let(:installation_with_organization) do
+    installations.create!(
+      client_key: 'baz',
+      base_url: 'https://example.com',
+      instance_url: 'https://example.com',
+      organization_id: organization.id
+    )
+  end
+
+  before do
+    ApplicationRecord
+      .connection
+      .execute('ALTER TABLE jira_connect_installations DROP CONSTRAINT IF EXISTS check_dc0d039821;')
+  end
+
+  after do
+    ApplicationRecord
+      .connection
+      .execute(
+        'ALTER TABLE jira_connect_installations ADD CONSTRAINT check_dc0d039821 ' \
+          'CHECK ((organization_id IS NOT NULL)) NOT VALID;'
+      )
+  end
+
+  describe "#up" do
+    it 'sets organization_id sharding key for records that do not have it' do
+      expect(installation_without_organization.organization_id).to be_nil
+      expect(another_installation_without_organization.organization_id).to be_nil
+      expect(installation_with_organization.organization_id).to eq(organization.id)
+
+      migrate!
+
+      expect(installation_without_organization.reload.organization_id).to eq(organization.id)
+      expect(another_installation_without_organization.reload.organization_id).to eq(organization.id)
+      expect(installation_with_organization.reload.organization_id).to eq(organization.id)
+    end
+  end
+end