On September 24, 1949, the XT-28 (company designation NA-159) was flown for the first time, designed to replace the T-6 Texan. The T-28A arrived at the Air Proving Ground, Eglin Air Force Base, Florida, in mid-June 1950, for suitability tests as an advanced trainer by the 3200th Fighter Test Squadron, with consideration given to its transition, instrument, and gunnery capabilities. Found satisfactory, a contract was issued and between 1950 and 1957, a total of 1,948 were built.
Following the T-28's withdrawal from U.S. military service, a number were remanufactured by Hamilton Aircraft into two versions called the Nomair. The first refurbished machines, designated T-28R-1 were similar to the standard T-28s they were adapted from, and were supplied to the Brazilian Navy. Later, a more ambitious conversion was undertaken as the T-28R-2, which transformed the two-seat tandem aircraft into a five-seat cabin monoplane for general aviation use. Other civil conversions of ex-military T-28As were undertaken by PacAero as the Nomad Mark I and Nomad Mark II