Nesbitt was born as William James Nesbitt to a Northern Irish family, his father was a teacher. Nesbitt himself wanted to become a teacher as well, so he began a degree in French at the University of Ulster. He dropped out of school after a year when he decided to become an actor. He graduated in 1987 and spent seven years performing in multiple plays. He made his film debut playing a talent agent in the 1991 comedy Hear My Song.
His notable roles include the title role of the BBC miniseries Jekyll, a modern-day sequel to Robert Louis Stevenson's novel The Strange Case of Dr. Jekyll and Mr. Hyde. He is also the host of a travel series touring around his native Ireland, and another touring around New Zealand, where he and his family lived for a year during the filming of the Hobbit trilogy.
Nesbitt is married to actress Sonia Forbes-Adam, who appears in the trilogy as Belladonna (Took) Baggins (Bilbo Baggins' mother). In October 2013, Nesbitt announced his separation from Forbes-Adam, though the couple are still legally married.
- Nesbitt joked that, now that every member of his family belongs to the cast of The Desolation of Smaug, they will henceforth be referring to themselves as "the von Nesbitts."
- One of Weta Workshop's makeup artists commented that Bofur's facial prosthetics were originally intended to be much more extensive, but Nesbitt had such an expressive face that these prosthetics were scaled down to leave most of his face uncovered.
- He appeared in the 1992-1993 TV series The Young Indiana Jones Chronicles, which also featured Christopher Lee and Anthony Daniels.
- He appeared in the 1997-2003 TV series Cold Feet, which also featured Richard Armitage.
- He appeared in the 2008 TV series Fairy Tales, which also featured Bernard Hill.
- He appeared in the 2008 TV serial The Passion, which also featured Joseph Mawle.
- He appeared in the 2014-2016 TV series The Missing, which also featured Ken Stott.
Richard Armitage • John Bell • Manu Bennett • Cate Blanchett • Orlando Bloom • Jed Brophy • Adam Brown • John Callen • Benedict Cumberbatch • Luke Evans • Martin Freeman • Stephen Fry • Ryan Gage • Mark Hadlow • Peter Hambleton • Craig Hall • Sir Ian Holm • Stephen Hunter • Robin Kerr • William Kircher • Sir Christopher Lee • Evangeline Lilly • Sir Ian McKellen • Graham McTavish • James Nesbitt • Mary Nesbitt • Peggy Nesbitt • Dean O'Gorman • Lee Pace • Mikael Persbrandt • Andy Serkis • Conan Stevens • Ken Stott • Aidan Turner • Hugo Weaving • Elijah Wood • Stephen Ure • John Rawls