Markell V. Efimoff (born August 22, 1988), known professionally as Mark L. Young, is an American actor.
Markell V. Efimoff () was born in Everett, Washington, of Russian descent. He has a fraternal twin, Arthur, and an older sister, Arlaris.
Young began acting at the age of nine and moved to Los Angeles when he was 12 to pursue his career. His first significant on-screen credit was a small role in two episodes of the HBO series Six Feet Under.
Young's other notable appearances include television shows The Comeback, The OC, Dexter, Big Love, Childrens Hospital, Heroes, Secret Life of the American Teenager, Cold Case, ER, ', and The Inbetweeners, while his film credits include Sex Drive, Happiness Runs, The Lucky Ones, We're the Millers, and Tammy.