Matthew died after a fall at Queenswood when he was only eight years old, which left the family grief-stricken. Soon after, Paul left home and went to live on his own in London, while his parents later divorced. He lived in a small flat and earned money by playing his guitar in the streets as a busker . After two years, he found a new job in a home for the elderly.
After appearing in the finale of Sean Bean's series Sharpe as HRH The Prince of Orange at the Battle of Waterloo, he made his film debut with a small part in Bent, a Holocaust drama which also featured Clive Owen, Jude Law, and Ian McKellen. He continued doing work in stage and television, these included Joe Penhall's Love and Understanding, which played at London's Flatbush Theatre and then ran in Connecticut. His roles in the television productions Killer Net and Coming Home – during which he met and dated Emily Mortimer. He did his last theatre work in One More Wasted Year and Stranger's House at the Royal Court Theatre.
Bettany had become addicted to cocaine along the way. His drug problem reached its height during the filming of the miniseries David Copperfield. After this he started to turn his back on drugs. He filmed several more movies, including his first leading role in Gangster No. 1. The British Independent Film Awards nominated him for Best Actor, and the London Critics Circle nominated him for British Newcomer of the Year.
Back in Hollywood, Oscar-winning writer/director Brian Helgeland (L.A. Confidential) was planning a new film called The Sin Eater (also known as The Order). He was impressed by Bettany's audition tape, though Bettany eventually decided to film A Knight's Tale instead. The studio executives were not impressed, but Helgeland was determined to cast him, even writing the part of Chaucer for him. A Knight's Tale would be Bettany's first big Hollywood production, and most American audiences would have their first look at Paul Bettany when he walked onscreen muddy and naked. "My buttocks entered the American market before I did," Paul joked on the movie's DVD commentary track.
He received critical acclaim for A Knight's Tale, including winning the London Critics Circle Award for British Supporting Actor. After the movie wrapped, Helgeland, determined that Hollywood should recognize Bettany's talent, showed the audition tape to many of his peers, including Ron Howard, who promptly cast Bettany in A Beautiful Mind. It was on that set that Bettany would befriend Russell Crowe and meet his future wife, Jennifer Connelly. Both were already in relationships, so they kept themselves only to friendship for about a year. Finally both single, they began dating. After A Beautiful Mind, Bettany was offered the role of the brutal serial killer "The Tooth Fairy" in Red Dragon, opposite Edward Norton and Anthony Hopkins. He turned down the role in favor of accepting a part with Stellan Skarsgård and Nicole Kidman in controversial director Lars Von Trier's Dogville.
Bettany's next major project saw him starring alongside Russell Crowe in Peter Weir's Master and Commander: The Far Side of the World. His portrayal of surgeon and naturalist Stephen Maturin brought in more critical acclaim, including a BAFTA nomination, British Actor of the Year (London Critics Circle), and Best Actor (Evening Standard).
On June 28, 2004, Bettany and thirteen other actors were included in the 2004 invitation to join the Academy of Motion Picture Arts and Sciences.
Dogville and The Reckoning were released in limited cinemas in 2004. In September of that year, Bettany made his leading-man debut in Wimbledon, a romantic comedy with Kirsten Dunst. Reviews for the movie were somewhat lukewarm, but every critic had praise for Bettany's performance. The film's cast would also introduce him to Jon Favreau, playing his manager, a relationship that would return when Favreau cast him as the voice of Jarvis in Iron Man. In spring 2005, Bettany went to Vancouver to film Firewall, a thriller starring Harrison Ford and Virginia Madsen, directed by Richard Loncraine (Wimbledon). He spent the autumn of 2005 filming The Da Vinci Code, based on Dan Brown's bestselling novel and starring Tom Hanks and Audrey Tautou. In the film he plays an Opus Dei monk called Silas. However, he was recently quoted in the Sun “I was brought up a Catholic. I’m lapsed. From the age of three I was with nuns. Now I’m an atheist.”
Bettany joined the New Line family fantasy Inkheart, playing the part of a fire-eater named Dustfinger.
In 2007, Bettany went to London to star in There For Me, written by his best friend Dan Fredenburgh, and Doraly Rosen.
| Year | Title | Role | Notes |
|---|---|---|---|
| 1997 | Bent | Captain | |
| Sharpe´s Waterloo | Prince William of Orange | Television movie-series | |
| 1998 | Coming Home | Edward Carey-Lewis | Television movie |
| Killer Net | Joe Hunter | Television mini-series | |
| The Land Girls | Philip | ||
| 1999 | Every Woman Knows a Secret | Rob | Television mini-series |
| After the Rain | Steph | ||
| 2000 | Kiss Kiss (Bang Bang) | Jimmy | |
| The Suicide Club | Shaw | ||
| David Copperfield | James Steerforth | Television movie | |
| Dead Babies | Quentin | ||
| Gangster No. 1 | Young Gangster | ||
| 2001 | A Beautiful Mind | Charles Herman | |
| A Knight's Tale | Geoffrey Chaucer | ||
| 2002 | Euston Road | "Y" | Short film |
| The Heart of Me | Rickie | ||
| 2003 | Master and Commander: The Far Side of the World | Dr. Stephen Maturin | |
| The Reckoning | Nicholas | ||
| Dogville | Tom Edison | ||
| 2004 | ''Wimbledon | Peter Colt | |
| 2006 | Firewall | Bill Cox | |
| The Da Vinci Code | Silas | ||
| 2008 | Iron Man | JARVIS (voice) | |
| Inkheart | Dustfinger | awaiting release | |
| The Secret Life of Bees | T. Ray Owens | awaiting release | |
| Broken Lines | Chester | awaiting release | |
| The Young Victoria | Lord Melbourne | post-production | |
| 2009 | Legion | Michael | post-production |