After the war was over, Feoktistov enrolled in the Bauman Moscow Higher Technical School as an engineering student and he graduated in 1949.

In 1964, Feoktistov was selected as part of a group of engineers for cosmonaut training, and in October of that same year, he was hastily assigned to the multi-disciplinary Voskhod 1 crew.

In October 1969, Konstantin Feoktistov and Georgi Beregovoi traveled as guests of NASA throughout the US, visiting any city they chose and Disneyland in California – they were joined on the trip by US astronauts as hosts, including Eugene Cernan, Neil Armstrong and others.

Kirk Douglas and others hosted receptions for them in Hollywood – they were protected by special agents of the US State Department on request of NASA.

Feoktistov resigned from his engineering position with Energia and then returned to Bauman Moscow Higher Technical School as a professor in 1990.