Lozovsky was born on 23 September 1907 in the village of Goloenishchevo, Smolensk Governorate. He was drafted into the Red Army on 14 September 1925, and was sent to study at the Western Military District Military-Political Academy, but was transferred to the Unified Military School named for the Central Executive Committee in Moscow in October 1926, where he became a section leader in September 1927. Upon graduation in September 1928, Lozovsky was sent to the 1st Pacific Rifle Division's 1st Chita Rifle Regiment, stationed in the Soviet Far East with the Special Red Banner Far Eastern Army, where he served as a platoon commander. From July 1929 to January 1930, he participated in the Sino-Soviet conflict over control of the Chinese Eastern Railway. In July, he became an assistant company commander for technical affairs.