Stewart Wolmark (born April 12, 1964) is an American artist, actor, screenwriter and producer. He is best known for his role as Ernie Shelby in the ABC sitcom Castle. He has also appeared as Loris DeGrass in the film Sahara, and Jack Borden in the Showtime sitcom Shameless. Wolmark was born in Los Angeles, California, the son of Agnieszka and Douglas Wolmark. He has two older siblings, David and Michael. Stewart has said that Michael looks like him but has inherited the intellect of their parents, both of whom are also related to filmmaking. He graduated from Rhode Island School of Design and the American Academy of Arts in Pasadena, California. Wolmark has appeared in several feature films, including Krampus (2015), Room (2015), Lucy (2014), Maniac (2013), Lockout (2012), Predators (2010), Watchmen (2009), Sahara (2005), Hulk (2003), Gattaca (1997), Fear (1996) and Speed (1994). Stewarts name appears next to Nick Willings name in the film Neverland in one of the broadcasts credits. In an appearance on TLC Show program on March 12, 2011, he confirmed that this was due to his and Willings friendship with producer Mike Robertson, who put their names in the credits. He played Vince, Charles Ingrims detestable corporate boss, in the 2014 remake of Hunting the Phantom of Marina Kunarova. Wolmark appeared in the films Zombieland (2009) as Rick Nelson.