Together with his Father, computer programmer Isai Scheinberg, he founded PokerStars in 2001. In June 2014, it was reported that Rational Group Ltd, the PokerStars parent company was being bought by Amaya Gaming Group of Canada for $4.9 billion. Scheinberg was CEO and 75% owner of Rational, which also owned Full Tilt Poker. As part of the deal, Scheinberg left Rational. According to Forbes, Scheinberg has a net worth of $4.5 billion, as of March 2017. As of May 2017, Scheinberg is the richest person on the Isle of Man.
Mark Scheinberg was born in Israel, the son of Isai Scheinberg, but moved to Toronto, Canada aged 13. They settled there in Richmond Hill, where in 2011 Isai still owned the house they had bought in 1988.
In May 2017, it was announced that Scheinberg was investing in a multimillion-dollar real estate project called Centro Canalejas Madrid in Madrid, Spain.