Many of his instructors were distinguished officers later, including Chesty Puller, Gilder D. Jackson Jr., Leonard B. Cresswell, Russell N. Jordahl, Howard N. Kenyon, and Roy M. Gulick.

[2] The Fourth Marine Regiment under colonel Samuel L. Howard arrived to the Philippine Islands at the beginning of December 1941, just few days prior the Japanese attack.

[2] Shofner was transported with the rest of captured Marines and soldiers to the prison camp and spent following eleven months at Bilibid, Cabanatuan and Davao Penal Colony.

He and nine other Americans (including William Dyess, Jack Hawkins, and Samuel Grashio) planned an escape, for which they spent two months smuggling food and equipment to a jungle cache.

From there they were guided by wild Ata tribesmen and friendly Filipinos to the headquarters of the 110th Division, 10th Military District, which was engaged in guerrilla warfare against the Japanese.

He then served on the staff of Camp Lejeune, North Carolina under Major General Henry L. Larsen and received promotion to the rank of lieutenant colonel in June 1944.

[2][10] Shofner was ordered back to the Pacific area during the next month and attached to the 1st Marine Division under Major General William H. Rupertus.

He also held additional duty as advisor on guerrilla affairs to the command of Douglas MacArthur and finally returned to 1st Marine Division just in time for the Battle of Okinawa in May 1945.

[2] Shofner returned to the United States in February 1946 and, following a brief leave at home, assumed duty as commanding officer of the post service battalion at Marine Corps Base Quantico under Major General Clifton B. Cates.

Upon his return to the United States, Shofner assumed duty as inspector-instructor of 1st Marine Reserve Battalion at Fort Schuyler in New York City.

In April 1952, Shofner took command of the headquarters and service battalion at the Marine Corps Recruit Depot Parris Island, South Carolina, under Major General Merwin H. Silverthorn.

Shofner assumed duty as commanding officer of 6th Marines in July 1957 and sailed to Turkey for Operation Deep Water, NATO naval exercise held in the Mediterranean Sea that simulated protecting the Dardanelles from a Soviet invasion, in September of that year.

Shofner worked as an executive in insurance and finance also was active in local Republican politics, the Sons of the American Revolution and the 1st Marine Division Association.