Fediaev received an engineering degree in air transport and Air Traffic Control from the Balashov Military Aviation School in 2004. Following graduation, Fediaev joined the Russian Air Force in the 317th mixed aviation segment. He obtained the rank of major before his retirement in 2013. He logged over 500 hours in Russian aircraft. Fediaev was selected as a cosmonaut in 2012. He reported to the Gagarin Cosmonaut Training Center in 2012 and was named a test cosmonaut on June 16, 2014. On July 15, 2022, he was assigned to the SpaceX Crew-6 mission after a recent crew swap agreement between NASA and Roscosmos.