In 1904, Leonid successfully auditioned for the Moscow Imperial Theater School. At only eight years old, he began his formal dance training. The next year, the director of the Bolshoi Theater, Alexander Gorsky, was looking for a small boy to play the role of Chernomor in the ballet "Ruslan and Ludmilla." Leonid was selected for the role. This performance and rehearsal period ignited his lifelong passion for acting. Leonid was selected for three more professional roles at the Bolshoi and Maly Theaters through the 1908–1909 season.