Mark Rendall fell into acting almost by accident when he was 10 years old. He told his parents that he would like to try acting, and they took him to audition for a touring production of the musical "Oliver". Despite his lack of training and experience, he landed the role of Spider, and understudy to Oliver. From there, his career took off; he first appeared on screen in 2000 in the short-lived comedy "The War Next Door", in a recurring role as the son to a secret agent. The next year, he had his first film role, when he starred in the children's fantasy "The Impossible Elephant". That same year, he also took on another recurring TV role in "Tales from the Neverending Story". In 2002, he had another major role, starring in the critically acclaimed drama "Touching Wild Horses", opposite Jane Seymour. Also that year, he got yet another recurring role, and also his first voice role, in the animated children's series "Arthur". In 2004, he gained major recognition for his starring performance as a troubled young television star in director Don McKellar's dark comedy, "Childstar". He also appeared that year for the first time in the sci-fi series "ReGenesis", as a boy who believes he's cloned, a role he reprised over seven episodes. Some other films he can be seen in include the 2007 drama "Silk", 2009's "The Exploding Girl", in which he had another starring role, and also in 2009, "The Year of the Carnivore".