In the years 1947-1948, the US Navy was finding that deliveries of its newly-ordered Grumman F9F Panthers and McDonnell F2H Banshee carrier-based jet fighters were taking place at a considerably slower rate than expected. In order to fill the gap until adequate numbers of these fighters could be delivered and to provide a nucleus of trained jet pilots, the Navy arranged for 50 U.S. Air Force F-80s to be transferred to them.

July 20, 1948 the first TO-1s were delivered to Marine Fighter Squadron 311 (VMF-311) at MCAS EI Toro, CA. The squadron was now ready to begin training Marine mechanics and west coast pilots in the rudiments of jet propulsion. The TO-1 served the squadron well. Over 300 pilots were trained with only one minor accident when this aircraft landed short of the runway, doing minor damage to the nose gear. On March 22, 1949 the F9F-2B Panther began to replace the TO-1 at VMF-311.

In September 1948 TO-1 33840 was accepted by the U.S. Navy at Lockheed's Vega Factory in Burbank, CA, and assigned to the USMC and VMF-311 at MCAS El Toro. In September 1950 '840 was transferred to the U.S. Navy and Jet Transitional Training Unit ONE (JTTU-1) at NAS Whiting Field, FL. During this period, the unit transitioned the U.S. Navy's Flight Demonstration team, ""Blue Angels,"" to jet aircraft. On Aug. 20, 1951, JTTU-1 moved to NAS Kingsville, TX, and was redesignated Advanced Training Unit THREE (ATU-3). Late in 1952, ATU-3 became ATU- 200. In July, 1954 '840 was placed into storage at NAF Litchfield Park. In April 1956, 33840 was stricken after accumulating 1,691 flight hours. In 1958 it went on display at the Cuyahoga County Airport near Cleveland, OH. In 1976 it was sent to the National Naval Aviation Museum in Pensacola, FL, for restoration. 1993 saw '840 return to MCAS El Toro and the Flying Leatherneck Aviation Museum and moved with the Museum in 2000 to its current location here at MCAS Miramar. This aircraft is on loan from the National Museum of the Marine Corps.