Beechcraft began designing the Model 25 early in 1940 in response to the requirement of the then-named United States Army Air Corps (USAAC) for a small twin-engined aircraft suitable for use in training student pilots in the handling of multi-engined retractable landing gear aircraft.

As there were concerns at the time about a future possible shortage of aluminium, part of the requirement was that the aircraft be built of "non-strategic" materials.

The following day Beechcraft began work on the Model 26, which was soon ready, making its first flight on 19 July the same year.

The type was accepted and deliveries began to the USAAF under the designation AT-10 in February 1942 at a time when US military fortunes were at their nadir.

By the end of 1942, 748 had been delivered and were playing a part in training crews for the vast fleets of bomber and transport aircraft that were pouring off factory production lines all over the United States.