After one-year internship in Bellevue Hospital and two years with the New York Dispensary, Moore entered the Army as assistant surgeon in 1853.

Then he was assigned to the Army of the Potomac and served as divisional chief surgeon at the battles of Antietam and Fredericksburg.

In June 1863 he became Medical Director of the Army of the Tennessee and later accompanied Maj. Gen. William T. Sherman on his famous "March to the Sea" and through the Carolinas.

In 1865 he received the brevet rank of colonel and was mustered out of the volunteer army with the close of the war.

Dr. Moore stayed in the regular army following the Civil War and served in a variety of medical posts, spending over a decade on assignment in New York City.