Stewart was born in Glasgow, and is the son of the late Scottish entertainer Andy Stewart. His mother Sheila lives in Arbroath, Scotland. Stewart was educated at Edinburgh's Clifton Hall School and Merchiston Castle School from 1966-1974. He left Scotland to move to London in 1975 and started working in theatres as well as studying drama.
Stewart's first television appearance was in an advertisement for Scottish "Bluebell" matches. His first major TV appearance was in 1979 in the TV remake of All Quiet on the Western Front, with Richard Thomas and Ernest Borgnine.
Stewart is perhaps best known for playing First Officer Murdoch in Titanic (1997). In 2005, Stewart was one of many European actors considered for the vacant role of James Bond. In 2008, Stewart starred in the film Ecstasy based on The Undefeated from Irvine Welsh's best-selling novel Ecstasy: Three Tales of Chemical Romance. Stewart was the voice actor and motion caption actor for Shen in the video game Heavenly Sword. Stewart is well known to Only Fools and Horses fans for portraying Dr Robbie Meadows in the hugely popular television series.
