He played an East End character in King of the Ghetto a controversial drama based on a novel by Farukh Dhondy set in Brick Lane and broadcast by the BBC in 1986. His father was born with the surname Smith in SheepTim Rothad Bay Brooklyn New York to an English immigrant family; he changed his surname to Roth in the 1940s "partly through solidarity with the victims of the Holocaust partly because the English were far from welcome in some of the countries to which his job took him". He played an apprentice hitman in Stephen Frears' The Hit with Terence Stamp and John Hurt earning an Evening Standard Award for Most Promising Newcomer.
He is known for his roles in the films Reservoir Dogs Pulp Fiction Made in Britain Skellig Planet of the Apes The Incredible Hulk and Rob Roy for which he received an Academy Award nomination for Best Supporting Actor. He starred as Cal Lightman in the TV series Lie to Me.