Wilkinson was born in Leeds, West Yorkshire. At the age of four, he moved with his family to Canada, where they lived for several years before returning to England and running a pub in Cornwall. Wilkinson graduated from the University of Kent, where he was a member of T24 Drama Society (then named UKCD) and attended the Royal Academy of Dramatic Art. Wilkinson currently lives in North London with his wife, actress Diana Hardcastle, and their two children.
Wilkinson made his television debut in the mid-1970s and worked on several British television series, most notably the mini-series First Among Equals (1986). He first gained critical acclaim with his appearance as Mr Pecksniff, in the BBC’s 1994 adaptation of Martin Chuzzlewit. He made only the occasional film (including a brief appearance in 1995’s Sense and Sensibility). After becoming part of the ensemble cast of the smash hit The Full Monty in 1997, a role which earned him a BAFTA, he began to take film roles more frequently, including supporting parts in Oscar and Lucinda, Wilde, Shakespeare in Love, and The Patriot.
His portrayal of the grief stricken father, Matt Fowler, in Todd Field’s In the Bedroom, received international praise from critics. For the role, he was named Best Actor of the Year by The New York Film Critics Circle, and went on to be nominated for the Academy Award for Best Actor. That success was followed up by Eternal Sunshine of the Spotless Mind, Normal, The Exorcism of Emily Rose, Batman Begins, and Separate Lies.
In 2007, Wilkinson played the manic depressive attorney Arthur Edens in Michael Clayton and garnered much critical acclaim and a nomination for the Academy Award for Best Supporting Actor. The same year, he played an uncle planning for murder in Woody Allen’s Cassandra's Dream.
He received a Doctor of Letters honorary degree from the University of Kent in July 2001. In the New Year’s Honours List published 31 December 2004, he was appointed an OBE for services to drama.
In 2008, Wilkinson portrayed American patriot Benjamin Franklin in the HBO mini-series John Adams. In the HBO movie, Recount, Wilkinson, with an uncanny resemblance, also portrayed American statesman and lawyer, James A. Baker, in Baker’s capacity as Chief Counsel to George W. Bush during the 2000 U.S. Presidential Election controversy, receiving an Emmy Award for the former and a nomination for the latter. He also received a Golden Globe Award and Screen Actors Guild Award nomination for his role in John Adams. Wilkinson stars in the horror comedy Burke and Hare, who is directed by John Landis. His 2010 role as Harvard professor / covert CIA high official in Roman Polanski’s The Ghost Writer was well noticed.