Early career O'Leary started as a
disc jockey at
BBC Essex, before becoming a
runner on the TV show
Light Lunch with
Mel Giedroyc and
Sue Perkins, and then a presenter at
Channel 4 as part of the original presenting line-up of the channel's
T4 strand. He moved on to present ''
Big Brother's Little Brother (the companion show to Big Brother'') on
E4 from 2001 onwards. Also in 2001, O'Leary appeared on
Lily Savage's
Blankety Blank. In 2004, O'Leary hosted the
reality television series
Shattered.
ITV On 29 March 2007, it was announced that O'Leary would replace
Kate Thornton as the new host of
ITV's
The X Factor for at least two series. On 27 March 2015, O'Leary confirmed that he had quit
The X Factor after eight years to pursue other projects. Via his Twitter account, he said: O'Leary was replaced by
Olly Murs and
Caroline Flack, who previously co-hosted
The Xtra Factor, the behind-the-scenes companion programme, together in 2011 and 2012. On 29 March 2016, O'Leary returned to
The X Factor as a presenter, replacing Murs and Flack, for the show's
13th series. In a statement, he said: From 2010 to 2019, O'Leary presented the
National Television Awards for ITV. Since 2010, O'Leary has hosted
Soccer Aid on ITV, a celebrity football match in aid of the charity
Unicef. In 2011, O'Leary hosted the Saturday night entertainment show
The Marriage Ref on ITV. In September 2013, O'Leary hosted
BRITs Icon: Elton John, a one-off music celebration for ITV. In 2013, O'Leary presented the ITV campaign
From the Heart, which encouraged viewers to consider organ donation. In January 2014, O'Leary filled in for
Phillip Schofield for a week when he guest presented
This Morning opposite
Holly Willoughby. In 2017, O'Leary co-presented the 37th
BRIT Awards with
Emma Willis. In March 2017, O'Leary guest-presented nine episodes of
The Nightly Show on ITV. In November 2020, it was announced that
Eamonn Holmes and
Ruth Langsford had been dropped from their Friday slot on
This Morning after 14 years.
Alison Hammond and O'Leary were announced to takeover the slot later that month. They presented their first show in January 2021.
Channel 4 On 27 November 2007, it was announced that
Big Brother: Celebrity Hijack was to be O'Leary's last series of
Big Brother. After seven years, he made his final
Big Brother appearance on 28 January 2008. In March 2007, O'Leary signed a year-long contract with Channel 4 to appear on
Hollyoaks. However, this was shortened after a series of disputes on set. Jim Rowe, a series writer at the time, said, "He couldn't follow even the simplest commands. It goes to show how vastly different presenting is to acting". O'Leary hasn't acted since. In 2009, O'Leary presented an episode of ''
The Paul O'Grady Show'', standing in for
Paul O'Grady. In March 2014, O'Leary made a return to Channel 4, where he presented the
Live From Space season for three consecutive nights.
BBC O'Leary was a presenter for
Comic Relief in 2005, 2011 and 2013. He also presented
Sport Relief in 2012. In August 2006, O'Leary signed a deal to present the game show
1 vs. 100, which aired on Saturday nights on
BBC One in combination with
The National Lottery Draws. In May 2009, O'Leary became the presenter of
Matt Lucas and
David Walliams's show
Rock Profile on BBC. In March 2010, O'Leary hosted a spin-off edition of the BBC One show
Question Time aimed at first time voters, which aired on
BBC Three. He also presented
Dermot Meets..., a series which saw him interview the likes of
David Cameron,
Gordon Brown, and
Nick Clegg. In November 2015, O'Leary replaced
Terry Wogan on
Children in Need due to Wogan's cancer-related ill health, from which he died a couple of months later. In 2016, O'Leary presented the BBC One Saturday night game show
The Getaway Car. The series was filmed in November 2015 and began airing in January 2016. He has also guest-presented two episodes of
The One Show with
Alex Jones.
Radio O'Leary joined London's
indie rock station
XFM in 2001, firstly presenting weekday mid-mornings from 10am to 1pm, before moving to a Saturday evening show in mid-2002, where he remained until late 2003. O'Leary joined
BBC Radio 2 in September 2004, presenting a Saturday afternoon show titled ''Dermot's Saturday Club'', which ran from 2pm to 4pm. Following a number of changes to the length and timing of O'Leary's programme, due in part to the arrival of
Chris Evans to Radio 2 and his role as presenter of
The X Factor, his show was broadcast between 3pm and 6pm from April 2009 until its end on 21 January 2017. It focused on new music and had featured live sessions. O'Leary also hosted Radio 2's coverage of the BRIT Awards and
South by Southwest. He won
Sony Gold Awards for Music Programme of the Year in 2008, 2010, and 2013. Since March 2017, O'Leary has presented the Saturday morning breakfast show on BBC Radio 2 between 8am and 10am, taking over the slot from
Brian Matthew and
Sounds of the 60s, which moved to an earlier time of 6am with
Tony Blackburn as presenter. Since April 2022 he has presented the weekly show ''Alternative Sounds of the 90s with Dermot O'Leary''.
Other work In March 2009, O'Leary introduced
Michael Jackson to an audience of fans at
The O2 in what turned out to be Jackson's final public appearance before
his death. In 2015, he was named one of
GQ's 50 Best Dressed Men in Britain. He has voiced television advertisements for
Amazon Prime. In 2017, he released a children's book called
Toto the Ninja Cat and the Great Snake Escape. In 2024, he released another children's book called
Wings of Glory. ==Charity work==