Francis Butler Loomis Jr. (June 21, 1903 – December 31, 1989) was a decorated officer of the United States Marine Corps, who reached the rank of major general.

He later lived in California and attended high school in San Mateo, before he was appointed to the United States Naval Academy in Annapolis, Maryland, in 1920.

While in China, he was appointed commander of the machine gun platoon and later was transferred as Student naval aviator to the Marine Observation Squadron 10.

He was ordered back to the United States in September 1928 and was assigned to the flight training at Naval Air Station Pensacola, Florida.

The 6th Marines sailed for expeditionary duties in China in August 1937 and Loomis was stationed in Shanghai as the part of defense forces of the International Settlement during Second Sino-Japanese War.

[1] He returned to San Diego in April 1938 and was appointed commanding officer of the Marine Detachment aboard the cruiser USS Pensacola.

After two years at sea, Loomis returned once more to San Diego in July 1940 and after promotion to the rank of major, he was appointed commanding officer of the 2nd Artillery Group in March 1941.

[1] He subsequently led his unit during the final phase of the Battle of Roi-Namur at the beginning of February 1944 and remained as occupation force on the Kwajalein and Majuro Atolls.

He was subsequently assigned to the staff of the III Marine Amphibious Corps (IIIMAC) under Major General Roy S. Geiger and participated in the Recapture of Guam at the end of July 1944.

However, change of orders came in December 1946, when he was transferred to San Francisco, California, and appointed senior inspector at the Headquarters of the Department of Pacific under general Keller E. Rockey.

Loomis remained in this capacity until July 1949, when he returned to the Chief of Naval Operations in Washington, D.C., as Marine Corps liaison officer for guided missiles and atomic energy.