John Thaddeus Walker was a highly decorated officer of the United States Marine Corps, who reached the rank of lieutenant general. He is most noted as commanding officer of the 22nd Marine Regiment during Battle of Eniwetok. He later served as director of personnel or commanding general of the Marine Corps Recruit Depot San Diego.

The 22nd Marine Regiment is an inactive United States Marine Corps infantry regiment. The regiment was commissioned in 1942 and was placed under the command of the 1st Provisional Marine Brigade in 1944, and the 6th Marine Division in 1945. It took part in fighting at the battles of Eniwetok, Guam, and Okinawa. The regiment also participated in the occupation of northern China following the war. 22d Marines was decommissioned in March 1946.