Lufbery served in the United States Army from 1907–1909 as a rifleman and saw service in the Philippines. He was first assigned from the recruit depot of Fort McDowell, Angel Island to Company F, 20th Infantry Regiment, at the newly established Fort Shafter, Territory of Hawaii on 13 December 1908. On 1 April 1909, he was stationed with Company M, at the Presidio of Monterey, California. In 1910, he was sent to Cuartel de España, Manila. After his time with the US Army, he saw India, Japan, and China.