diff --git a/changelogs/unreleased/sh-store-user-in-api-logs.yml b/changelogs/unreleased/sh-store-user-in-api-logs.yml
new file mode 100644
index 0000000000000000000000000000000000000000..d904dcaf6d361b4e2291b093e3c7e233722bcc02
--- /dev/null
+++ b/changelogs/unreleased/sh-store-user-in-api-logs.yml
@@ -0,0 +1,5 @@
+---
+title: Save user ID and username in Grape API log (api_json.log)
+merge_request:
+author:
+type: changed
diff --git a/lib/api/api.rb b/lib/api/api.rb
index e0d14281c96128e73177706996e6e7588df5a42a..ae161efb35815ea0cd77a1dbad34d2780d11e077 100644
--- a/lib/api/api.rb
+++ b/lib/api/api.rb
@@ -13,7 +13,8 @@ module API
         formatter: Gitlab::GrapeLogging::Formatters::LogrageWithTimestamp.new,
         include: [
           GrapeLogging::Loggers::FilterParameters.new,
-          GrapeLogging::Loggers::ClientEnv.new
+          GrapeLogging::Loggers::ClientEnv.new,
+          Gitlab::GrapeLogging::Loggers::UserLogger.new
         ]
 
     allow_access_with_scope :api
diff --git a/lib/api/helpers.rb b/lib/api/helpers.rb
index bf388163ec839110c420618362d157cf9929a31c..d6ce368efd59bb3e4ca132f5729f6739fbcf7381 100644
--- a/lib/api/helpers.rb
+++ b/lib/api/helpers.rb
@@ -5,6 +5,7 @@ module API
 
     SUDO_HEADER = "HTTP_SUDO".freeze
     SUDO_PARAM = :sudo
+    API_USER_ENV = 'gitlab.api.user'.freeze
 
     def declared_params(options = {})
       options = { include_parent_namespaces: false }.merge(options)
@@ -48,10 +49,16 @@ module API
 
       validate_access_token!(scopes: scopes_registered_for_endpoint) unless sudo?
 
+      save_current_user_in_env(@current_user) if @current_user
+
       @current_user
     end
     # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
+    def save_current_user_in_env(user)
+      env[API_USER_ENV] = { user_id: user.id, username: user.username }
+    end
+
     def sudo?
       initial_current_user != current_user
     end
diff --git a/lib/gitlab/grape_logging/loggers/user_logger.rb b/lib/gitlab/grape_logging/loggers/user_logger.rb
new file mode 100644
index 0000000000000000000000000000000000000000..fa17286196774b79208548595e0d9ab0762b1a55
--- /dev/null
+++ b/lib/gitlab/grape_logging/loggers/user_logger.rb
@@ -0,0 +1,18 @@
+# This grape_logging module (https://github.com/aserafin/grape_logging) makes it
+# possible to log the user who performed the Grape API action by retrieving
+# the user context from the request environment.
+module Gitlab
+  module GrapeLogging
+    module Loggers
+      class UserLogger < ::GrapeLogging::Loggers::Base
+        def parameters(request, _)
+          params = request.env[::API::Helpers::API_USER_ENV]
+
+          return {} unless params
+
+          params.slice(:user_id, :username)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/requests/api/helpers_spec.rb b/spec/requests/api/helpers_spec.rb
index 0462f494e1593f490d9c550d01a2d2324d534307..837389451e8420fadbf1ffd935aa52da088d608a 100644
--- a/spec/requests/api/helpers_spec.rb
+++ b/spec/requests/api/helpers_spec.rb
@@ -68,6 +68,12 @@ describe API::Helpers do
           end
 
           it { is_expected.to eq(user) }
+
+          it 'sets the environment with data of the current user' do
+            subject
+
+            expect(env[API::Helpers::API_USER_ENV]).to eq({ user_id: subject.id, username: subject.username })
+          end
         end
 
         context "HEAD request" do