Derived from the B-58 Hustler bomber, it was designed in 1961 but no examples of the type were ever built.

The Model 58-9 was Convair's proposal for the third step in a three-step program for the development of a SST based on the company's B-58 Hustler supersonic medium bomber.

[2] Proposed during early 1961, the Model 58-9 would use the wing design of the B-58C, which would be mated to an entirely new fuselage and tail; the airliner's cabin would be capable of seating as many as 52 passengers.

[3] The Model 58-9 was expected to have a maximum take-off weight of 190,000 pounds (86,000 kg), and would have a range of 2,500 nautical miles (4,600 km; 2,900 mi) at a cruising speed of Mach 2.4.

It was expected that the Military Air Transport Service would perform simulated airline flights using the Model 58-9 during its development.