The T-34 was the brainchild of Walter Beech, who developed it as the Beechcraft Model 45, a private venture at a time when there was no defense budget for a new trainer model. Beech hoped to sell it as an economical alternative to the North American T-6/SNJ Texan, then in use by all services of the U.S. military.

The basic aircraft began use in the late 1940s in South American countries, Japan, Spain and Turkey. In March 1953, the USAF ordered it as its new primary trainer, with the T-34A Mentor designation. Early versions of the T-34, dating from around the late 1940s to the 1950s, were piston driven with a Continental O-470, 225 hp engine; a total of 450 were acquired by the USAF but another 1,454 were built by companies in other countries for their use.

In 1954, the Navy acquired 423 of the T-34Bs. In 1973, Beech received a Navy research contract to see if the aircraft could be fitted with a 400 h.p. Pratt and Whitney turboprop engine and the latest electronics equipment. These were designated the T-34C Turbo-Mentor. In 1975, the Navy switched to the T-34C as their primary pilot trainer.

A T-34C-1 armament systems trainer version was developed with four underwing hard points for bombs, rockets, flares, anti-tank rockets and gun pods. They were widely exported.

The T-34 was replaced by the T-37 jet trainer by the USAF in the late 1950s and by the T-6 Texan II for the Navy in the mid-1980s.