Stephen Koerner, Acting Director of Nasa’s Johnson Space Center, thanked Mr Wilmore for his dedication to space exploration.
“His lasting legacy of fortitude will continue to impact and inspire the Johnson workforce, future explorers, and the nation for generations,” he said.
Mr Wilmore retires at the age of 62, which is almost 20 years older than the average age for astronauts, with candidates usually selected between the ages of 26 and 46.
He served as a test pilot before being selected by Nasa to become an astronaut in 2000.
His last mission was taking part in the first crewed test flight of the Starliner spacecraft with Ms Williams last year before the capsule suffered technical problems as it approached the ISS.
“Docking was imperative,” Mr Wilmore told BBC News in May. “If we weren’t able to dock, would we be able to make it back? We didn’t know.”