Bertonov was born on March 16 1881 in Vilna (Vilnius, Lithuania),[1][2] then part of the Russian Empire. He acted in the Russian municipal theater in Vilna from 1905 to 1911.[2] After initially playing small roles, he was at one point unexpectedly called upon to play the role of Shmaga in Alexander Ostrovsky's play Guilty Without Guilt, filling in for an actor who had fallen ill; the performance was such a success that he henceforth became the lead comic actor of the troupe.[2]