Campbell was born in Glasgow, to an Iranian father, Booth Danesh, and a Scottish mother, Avril Campbell; his family live in Bearsden. The eldest of three boys, his younger brothers are Aria (b. 1985) and Cyrus (b. 1995). He attended Bearsden Primary School and the Glasgow Academy, before going on to study English Literature and Philosophy at the University of Edinburgh.
His professional career began with a non-singing role of the Scottish Opera's avant garde 1990s production of The Trojans. As a teenager he then performed at Covent Garden Royal Opera House with the Scottish Opera in a production of Carmen.
He first gained fame in 2001 after appearing on the British talent competition Popstars. A year later he was voted to the finals of the TV talent show, Pop Idol. He turned down Simon Cowell's record deal, then signed with producer Steve Lillywhite.
The first single written by Campbell, Colourblind, was released on 29 July 2002 and entered the UK singles chart at number 1, staying at the top of the charts for two weeks, it was certified silver.
His debut album, Dive In, was certified platinum in the UK in 2004, charting at number 6 in the UK albums chart during the competitive pre-Christmas sales. He has subsequently had five UK Top Ten singles and a second gold album.
He wrote all 12 songs on the Dive In album and produced one of the tracks called Better Than That whilst collaborating with a number of other producers such as The Misfits and The Matrix on the other tracks. Steve Lillywhite was executive producer on the album. Campbell, then performing as Darius Danesh, supported Shakira on her world tour and went on to complete his own sell-out UK Dive In Tour.
The Dive In Tour took place in April and May 2003. The fifteen dates scheduled for May expanded to twenty three dates on public demand.
His book Sink or Swim, about the perils of the music business, was a Sunday Times sixth best seller. He contributed to the War Child charity album with Coldplay and Oasis and headlined in India with Alanis Morissette after his album went platinum there.
After receiving news that his father was diagnosed with terminal cancer, he wrote and dedicated his second studio album Live Twice to Dr Booth Danesh. In 2005, the album's title-track Live Twice became his fifth Top Ten single.
Campbell had two West End runs in Chicago during 2005-2006, and at 25, became the youngest actor to fill the role of Billy Flynn since the show first opened on Broadway in 1975.
In 2007, after seeing Ewan McGregor in the role, he played the lead in Michael Grandage's Olivier Award-winning production of Guys and Dolls, starring as Sky Masterson. Later that year he reprised his role of Billy Flynn for the 10th Anniversary charity performance of Chicago in London, to benefit the charities Breast Cancer Haven and Breast Health Institute.
In 2008 he returned to London's West End to play Rhett Butler in Sir Trevor Nunn's musical adaptation of Gone With The Wind.
In January and February 2010 Campbell won the UK's ITV1 talent show Popstar to Operastar, in which eight pop stars were trained to perform famous opera arias. He was mentored by tenor Rolando Villazón, with whom he went on to duet with on the song "The Impossible Dream". In May 2010 he appeared as toreador Escamillo in Bizet's opera Carmen at The O2 arena in London. At 29, he became the youngest performer to assume the lead role of Carmen's lover, a role more often awarded to a baritone in his forties. Also in 2010 he starred in The History of the Big Bands tour – a show about the Big Band and Swing Era, featuring the songs of Frank Sinatra and the music of the key musicians of the big band era, including music from Harry James, Benny Goodman, Tommy Dorsey, Duke Ellington, Glenn Miller, Count Basie, Woody Herman and Buddy Rich.
On 1 July 2013, it was announced that Campbell would play the lead role of Warden in the show From Here to Eternity the Musical.
Darius is currently playing Nick Arnstein in Funny Girl (Musical) at the Savoy, following a transfer from the Menier Chocolate Factory in April 2016.
In 2003 Campbell appeared as himself in an episode of the Channel 4 soap Hollyoaks, performing 'Girl in the Moon' at a graduation ball. In 2009 he guest-starred on the BBC show Hotel Babylon, starring as Gennaro Fazio, an Italian magazine editor.
In January and February 2010 Campbell competed in and won the ITV talent show Popstar to Operastar, in which eight pop stars were trained to perform world-famous opera arias. He was mentored by world-leading tenor Rolando Villazón, with whom he went on to duet with on the song "The Impossible Dream".
Campbell is an Ambassador for The Prince's Trust, helping underprivileged youth. He has designed a guitar for Guitar Aid. He works with and supports the Lymphoma Association and Cancer Research UK amongst other cancer charities.
Campbell was married to Canadian actress Natasha Henstridge. Campbell and Henstridge married in a secret ceremony in February 2011. The couple filed for divorce in July 2013.Dive In (2002)
Live Twice (2004)