Alexander Garnaev was born in Zhukovsky town of Moscow Region. Since 1977 served in Army. In 1981 graduated from Armavir high military aviation pilot school. Served in Air force front-line units (till 1985). In 1987 graduated from Test-pilot school, in 1989 graduated from MAI.
In 1987-1994 worked as test-pilot at A.I. Mikoyan EDB. Tested more than twenty five plane types. Participated in testing MiG-29M, MiG-31B, MiG-29LL. Tested armament on MiG-27, MiG-29 and MiG-31.
Since 1994 works as test-pilot at M.M.Gromov FRI.