Leonid Isaakovich Yarmolnik was born on January, 22nd, 1954 into the family of a Soviet Army officer in Grodekovo Town of the Primorski Territory. In the 1960s the Yarmolniks family moved to Lvov. Leonid studied at a music school, was fond of literature and theater, and attended a drama studio at the Lvov Folk Theater. In 1971 he tried to enter the Leningrad State Institute of Theatre, Music and Cinema, but failed. However, next year he was admitted to the Schukin Theatrical College, where his teachers were Yury Katin-Yartsev, Vladimir Etush, Mikhail Ulyanov, and others.

Upon graduation in 1976 Leonid Yarmolnik was distributed to Taganka Theatre, with Yuri Lyubimov as the chief stage director at that time. The actor worked in Taganka Theater till 1984.
From 1993, Leonid Yarmolnik worked a lot on television, where he was invited by the renowned journalist Vlad Listyev. Among the competitive and entertaining telecasts hosted by Leonid Yarmolnik one should mention the popular L-Club – his debut work as a host - and Gold-Rush, somewhat similar to Fort Boyard telecast.
The film Moscow Vacation (1995) starring Leonid Yarmolnik was his great creative success and also showed his talent as the film producer, who had to apply considerable resourcefulness while arranging the shootings in Russia and Italy.
Leonid Yarmolnik also produced a number of other films, founded the L-Club studio, was the president of the TV company Promotion Group, and released CDs with classical works played by famous performers.
Yarmolnik is the winner of the State Award of the Russian Federation, Gold Ram Prize, Nika Award, and other prizes. In spite of being busy Leonid has lots of hobbies, giving preference to diving and billiards. His wife Oksana is a theatre costume designer.