Zaitsev was born in 1923 and attended middle school before volunteering for the Soviet Army in 1941. In May 1942, Zaitsev was transferred to the combat arms and served as a staff officer in the 113th Tank Brigade and later the 7th Guards Tank Corps. He was transferred to the headquarters of the 6th Guards Tank Corps. Zaitsev took part in the battles of Kursk and Berlin, as well as major Soviet operations such as Lvov-Sandomierz, Vistula-Oder, and the drive on Prague. Zaitsev ended his wartime service assigned to the 1st Ukrainian Front.