Born in the town of Ozerki, Kursk Governorate, Russian Empire. Honored Artist of the RSFSR (1956). People's Artist of the RSFSR (1970). On stage since 1920. In 1925 he graduated from the Moscow Theater Technical School named after A.V. Lunacharsky and until 1932 was an actor in various amateur arts houses. In 1932-1936 - actor at the Theater of the All-Union Central Council of Trade Unions. In 1936-1941 and 1943-1959 - actor at the Central Academic Theater of the Soviet Army. Although Nikolai Sergeyev first appeared in film in 1937, debuting as the commander of a fascist squadron in the film "Deep Raid", it was his older-character roles that brought him fame. A milestone in this regard for him was the role of the old worker Basmanov in Iosif Kheifits's film "The Big Family" (1954). In this film the actor was noticed by Mikhail Shveitser, who gave him a completely opposite image to create - that of the stingy peasant Silanty Ryashkin in "Someone Else's Kin" (1955).

From that moment leading Soviet directors began to invite Nikolai Sergeyev, and he soon left the theater for cinema. For more than fifty years Nikolai Vasilyevich lived in a happy marriage with the actress Olga Vasilyevna Dolgova, with whom he worked together at the Central Theater of the Soviet Army. When Sergeyev began to act actively and left the theater, she left with him, giving up her profession, and devoted the rest of her life to caring for her husband. The couple had no children, so when their niece Svetlana appeared in their home in the late 1950s, they redirected all their love and care to her. Buried at the Vagankovo Cemetery (section 26).