Peck was appointed to the United States Naval Academy at Annapolis, Maryland, by President William Howard Taft and graduated with a bachelor's degree in June 1915 as a second lieutenant in the Marine Corps.

[1] Some of his classmates also became general officers later: Arthur C. Davis, Francis S. Low, Lynde D. McCormick, Arthur D. Struble, Ralph W. Christie, John L. McCrea, Ralph J. Mitchell, Harvey Overesch, Pedro del Valle, Howard L. Vickery, Richard W. Bates, Henry P. Burnett, Archie F. Howard, Oliver H. Ritchie, James M. Shoemaker, Scott Umsted and Raymond R.

Upon his graduation, he served as an instructor at Marine Corps School until 1927, when he was assigned for studies to Command and General Staff College at Fort Leavenworth, Kansas.

As an experienced teacher, he remained at the Naval War College as an instructor until June 1938, when he was assigned to the Fleet Marine Force in San Diego.

[2] Peck was subsequently relieved by Colonel Samuel L. Howard on May 13, 1941, and returned to Washington, D.C., where he was attached to the staff of the commander in chief, United States Fleet, Admiral Ernest King.

He subsequently participated in the planning of the allied advanced to the Central Solomon Islands for the upcoming New Georgia Campaign and flew from Pacific to Washington, D.C., in January 1943 to present the outline of the operation.

[4] Peck also requested additional forces necessary to assault Japanese positions in the New Georgia Islands, but his plea was rejected by the Joint Chiefs of Staff (Marshall, King, Leahy and Arnold).

In March 1943, he flew with Vice Admiral Turner for a meeting at Pearl Harbor, where they introduced their plan to the USAFFE Commander, General Douglas MacArthur, who approve it.

[4] Peck remained in the Pacific until July 1943, when he was ordered to Washington, D.C., and appointed to Headquarters Marine Corps as director of the Division of Plans and Policies.

However, the surrender of Japan on August 15, 1945, changed those plans, and Peck with his 1st Division were sent to supervise the disarmament and repatriation of Japanese troops in North China in September of that year.

[7] After a few months of medical leave in the United States, Peck finally retired from the Marine Corps on November 5, 1946, with the rank of major general.