He commanded the Apollo 8 mission (see apollo project) that made the first crewed flight around the Moon, in 1968. He previously commanded, in 1965, a Gemini 7 endurance flight, piloted by James Lovell. Borman spent 14 days in orbit and made the first space rendezvous, with Gemini 6 astronauts. He was selected as an astronaut in 1962.

Borman was subsequently appointed deputy director of NASA's Flight Crew Operations Branch. He left NASA in 1969.