North American initially produced the NA-16 trainer as a private venture in 1935. The Navy first ordered a version of the this trainer late in 1936, with a contract for 40 NJ-1 with fixed landing gear, fabric covered rear fuselage, and the 500 hp Pratt & Whitney R-1340 Wasp engine. These were used as trainers at Pensacola NAS and as command and staff transports. The Navy ordered 16 improved SNJ-1 models with retractable landing gear and full metal fuselage in 1938 which were assigned to the 13 Naval Reserve Air Bases. An additional 36 of the SNJ-2 models with the 550 hp Pratt & Whitney R-1340-56 wasp engine were ordered in 1939 for the reserve training bases. 40 additional SNJ-3 models were ordered in 1940. The final Navy version of the North American trainer was the SNJ-6 produced in 1944. It had strengthened wing panels and a redesigned rear fuselage. The Navy SNJs remained in service in large numbers well into the fifties as primary, basic, and instrument trainers
The North American Aviation SNJ trainer was the primary pilot instruction trainer used by all branches of the US military services from its delivery in 1935 throughout the war
North American Aviation produced over 17,000 of these trainer aircraft for the Navy, Army, and Air Force as well as for the British, Canadian, and Australian air forces.