[2] His father was Aleksandr Fyodorovich Orlov (1855–1940), member of Narodnaya Volya, official of Udel department of Vologda and Arkhangelsk Governorates.

His mother was Vera Pavlovna Tumarkina (1862–1899), from Bessarabian Jewish merchants family, the older sister of Anna Tumarkin.

Orlov studied zoology and anatomy at the State University of St. Petersburg under Alexei Zavarzin.

He then taught from 1916 to 1924 at the Medical Faculty of the University of Perm, during the Russian Civil War turmoil under some very difficult conditions.

From 1925 he devoted his research interests to paleontology, the old love of his youth, and joined Aleksei Borisyak.