Nighy was born on 12 December 1949 in Caterham, Surrey. His mother, Catherine Josephine Nighy (née Whittaker), was a psychiatric nurse who was born in Glasgow, and his English-born father, Alfred Martin Nighy, managed a car garage after working in the family chimney sweeping business. Also of part Irish descent, Nighy was brought up as a Roman Catholic, serving as an altar boy.
He has two older siblings, Martin and Anna. Nighy attended the John Fisher School, a Roman Catholic grammar school in Purley, where he was a member of the school theatre group. He left the school with two O-levels and then took a job with The Croydon Advertiser as a messenger boy. He went on to train at the Guildford School of Acting.
After two seasons at the Everyman Theatre, Liverpool, Nighy made his London stage debut at the National Theatre in an epic staging of Ken Campbell and Chris Langham's Illuminatus!, which opened the new Cottesloe Theatre on 4 March 1977, and went on to appear in two David Hare premieres, also at the National. During the 1980s, he appeared in several television productions, among them Hitler's SS: Portrait in Evil, alongside John Shea and Tony Randall.
He has starred in many radio and television dramas, notably the BBC serial The Men's Room (1991). He claimed that the serial, an Ann Oakley novel adapted by Laura Lamson, was the job which launched his career. More recently he has featured in the thriller State of Play (2003) and costume drama He Knew He Was Right (2004). He played Samwise Gamgee in the 1981 BBC Radio dramatisation of The Lord of the Rings (where he was credited as William Nighy), and appeared in the 1980s BBC Radio versions of Yes Minister episodes. He starred alongside Stephen Moore and Lesley Sharp in the acclaimed short radio drama Kerton's Story, first aired in 1996. He had a starring role in the 2002 return of Auf Wiedersehen, Pet, portraying crooked politician Jeffrey Grainger. He has also made a guest appearance in the BBC Radio 4 series Baldi.
Two of Nighy's most acclaimed stage performances were in National Theatre productions. As Bernard Nightingale, an unscrupulous university don, in Tom Stoppard's Arcadia (1993), he engaged in witty exchanges with Felicity Kendal, who played the role of Hannah Jarvis, an author; and he played a consultant psychiatrist in Joe Penhall's Blue/Orange (2000), for which he won an Olivier Award nomination for Best Actor, and which transferred to the West End at the Duchess Theatre the following year.
Nighy received some recognition by American audiences for his acclaimed portrayal of overaged rock star Ray Simms in the 1998 film Still Crazy. In 1999 he gained further prominence in the UK with the starring role in "The Photographer", an episode of the award-winning BBC-TV mockumentary comedy series People Like Us, playing Will Rushmore, a middle aged man who has abandoned his career and family in the deluded belief that he can achieve success as a commercial photographer.
In 2003, Nighy played the role of the Vampire Elder Viktor in the American production Underworld. He returned in the same role in the sequel Underworld: Evolution in 2006, and again in the prequel Underworld: Rise of the Lycans in 2009. In February 2004, he was awarded the BAFTA Film Award for Best Supporting Actor for his role as Billy Mack in Love Actually (a role foreshadowed by his Still Crazy character) and followed this up at the BAFTA Television Awards in April with the Best Actor award for State of Play. He also appeared in the comedy Shaun of the Dead.
In early 2004, The Sunday Times reported that Nighy was on the shortlist for the role of the Ninth Doctor in the 2005 revival of the BBC television series Doctor Who. Christopher Eccleston ultimately filled the role.
In 2005, he appeared as Slartibartfast in the film adaptation of The Hitchhiker's Guide to the Galaxy. He also appeared in the one-off BBC One comedy-drama The Girl in the Café. In February 2006, he appeared in scriptwriter Stephen Poliakoff's one-off drama, Gideon's Daughter. Nighy played the lead character, Gideon, a successful events organiser who begins to lose touch with the world around him. This performance won him a Golden Globe Award for Best Actor in a Mini-series or TV Film in January 2007. Also in 2006, Nighy made his Broadway debut at the Music Box Theatre alongside Julianne Moore in The Vertical Hour, directed by Sam Mendes.
In 2006, Nighy played the principal villain, Davy Jones, in Pirates of the Caribbean: Dead Man's Chest, although his face was entirely obscured by computer-generated makeup; he voiced the character with a Scots accent. He reprised the role in the 2007 sequel, Pirates of the Caribbean: At World's End, in which his real face was briefly revealed in one scene. He also provided the narration for the Animal Planet series Meerkat Manor. In 2006 he played the role of Richard Hart in Notes on a Scandal, for which he was nominated for a London Film Critics' Circle award. Nighy also appeared as General Friedrich Olbricht, one of the principal conspirators, in the 2008 film Valkyrie. He had played an SS officer in the 1985 Hitler's SS: Portrait in Evil. Nighy starred in the film Wild Target in 2010.
In July 2009, he announced that he would play Rufus Scrimgeour in Harry Potter and the Deathly Hallows – Part 1. Nighy had already worked with director David Yates twice, and with the majority of the Harry Potter cast in previous films. He has said of his role as Rufus Scrimgeour that it meant he was no longer the only English actor not to be in Harry Potter.
Nighy voiced Grandsanta in the 2011 CGI animated film Arthur Christmas. In 2012, he starred in The Best Exotic Marigold Hotel, Wrath of the Titans, and the remake of Total Recall. In 2013, he played a role in Darkside, Tom Stoppard's radio drama based on Pink Floyd's album The Dark Side of the Moon.
Nighy had a 27-year-relationship with English actress Diana Quick, with whom he has a daughter, actress Mary Nighy. The couple separated amicably in 2008.
He is a supporter of Crystal Palace and is the Patron of the CPSCC (Crystal Palace Children's Charity), and of the Ann Craft Trust. He is also one of the Honorary Patrons of the London children's charity Scene & Heard. He has Dupuytren's contracture, a muscular condition which can, depending on the condition's severity, develop so that the ring and little finger of each or both hands are partially or permanently folded towards the palm.
Nighy is also a patron for the Milton Rooms, a new arts centre in Malton, North Yorkshire, along with Imelda Staunton, Jools Holland and Kathy Burke.
Known for his support of total gender equality, Nighy noted in an interview during the 2016 DIFF film festival that the highlighting of the gender inequality problem had been a factor in his choice of films.
Nighy is noted for his bespoke navy suits. He was listed as one of the fifty best-dressed over 50s by The Guardian in March 2013 and one of GQ's 50 best dressed British men in 2015.The Plaza Suite by Neil Simon – Watermill Theatre, Newbury
The Milk Train Doesn't Stop Here Anymore by Tennessee Williams – Watermill Theatre, Newbury
Landscape and Silence, by Harold Pinter – Gateway Theatre, Chester
Entertaining Mr Sloane by Joe Orton – Gateway Theatre, Chester
Rosencrantz & Guildenstern Are Dead, by Tom Stoppard – Arts Theatre, Cambridge
The Immoralist, from the novel by André Gide – Hampstead Theatre
Speak Now, by Olwen Wymark – Traverse Theatre, Edinburgh (1971)
Freedom of the City, by Brian Friel – Everyman Theatre, Liverpool
Under New Management, by Chris Bond – Everyman Theatre, Liverpool
Occupy! – Liverpool Everyman Theatre (1976)
Illuminatus!, Ken Campbell/Chris Langham – NT Cottesloe (The theatre's first production, 1977)
Comings and Goings, by Mike Stott – Hampstead Theatre Club (1978)
The Warp, by Neil Oram/ Ken Campbell – ICA (1979)
Illuminations, by Arthur Rimbaud – Lyric Hammersmith (1980)
A Map of the World, by David Hare – NT Lyttelton (1983)
Pravda, by David Hare/ Howard Brenton – NT Olivier (1985)
King Lear, by William Shakespeare – NT Olivier (1986)
Mean Tears, by Peter Gill – NT Cottesloe (1987)
Betrayal, by Harold Pinter – Almeida Theatre, London (1991)
Arcadia, by Tom Stoppard – NT Lyttelton (1993)
The Seagull, by Anton Chekhov/ad. Pam Gems – NT Olivier (1994)
Skylight, by David Hare – NT production at Vaudeville Theatre, London (1995)/ UK tour (1997)
A Kind of Alaska, by Harold Pinter – Donmar Warehouse (1998)
Blue/Orange, by Joe Penhall – NT Cottesloe (2000), Duchess Theatre (2001)
The Vertical Hour, by David Hare, Broadway production at the Music Box Theater, NY (2006)'
Skylight, by David Hare – West End production at Wyndham's Theatre (2014)
Skylight, by David Hare – Broadway production at John Golden Theatre (2015)