Carr was born in Weymouth, Dorset, and grew up partly in Northampton where he went to Weston Favell School. His father is former Northampton Town and Nuneaton Borough F.C. manager Graham Carr. Carr has a younger brother, Gary.
Carr moved to Manchester after a string of dead end jobs in Northampton seeking a better life and with aspirations of becoming a comedian. He moved into a house full of activity in Chorlton-cum-Hardy after which he moved to Stretford; which he cites as an inspiration for his comedic work. Carr gained a BA (Hons) degree in Drama and Theatre Studies, graduating with a 1 from Middlesex University.
Despite being openly gay and very camp, he doesn't consider his sexuality to be a focal part of his act, once saying that "I just think gay people need to get over themselves. Just because you're gay and on the telly doesn't mean you're a role model. I'm just a comedian. That's all I am. ... What am I meant to do? Do I go down the Julian Clary route and talk about fisting and poppers? I don't talk about being gay and I think what better equality for gays than that?".
On 21 September 2006, Carr and entertainer Lionel Blair helped save a man who was about to fall from a pier in Blackpool. The man was holding on by his fingertips, but the two men managed to pull him to safety.
Carr made his radio presenting debut on Christmas Day 2007 for BBC Radio 2 as part of their Festive Highlights, with the show Alan Carr's Christmas Box. He also filled in on BBC 6Music on 16 February and 14 June 2008 for Adam and Joe and co-presented The Russell Brand Show on 4 October 2008. He also presented Alan Carr's Comedy Outings for BBC Radio 2 in 2008. On 25 April 2009, Carr began hosting Going Out With Alan Carr, a new show for BBC Radio 2, in conjunction with Emma Forbes. The show is broadcast every Saturday evening from 6pm-8pm.
Carr performs stand-up regularly, on tour and on television. He has been featured in three Edinburgh shows and in 2007 he toured throughout the UK, which was followed by a DVD entitled "Tooth Fairy Live". Carr had his own monthly show in a Manchester comedy club and he has toured nationwide, supporting other acts. He has performed at the Apollo Theatre in London, which was televised for the BBC1 series 'Live At The Apollo', and has been featured in the Royal Variety Performance.
Carr has appeared and performed at many festivals, including the Reading and Leeds Festivals, Latitude Festival, the Kilkenny Comedy Festival and Live Earth, where he welcomed musical acts David Gray and Damien Rice on stage. He has performed stand-up internationally, including an appearance at the Montreal 'Just For Laughs' festival.
On 4 September 2009, Carr switched-on the Illuminations in Blackpool along with JLS.
In 2010, Carr took part in Channel 4's Comedy Gala, a benefit show held in aid of Great Ormond Street Children's Hospital, filmed live at the O2 Arena in London on 30 March.
In December 2008 Carr, when accepting his award for Best Entertainment Personality at the British Comedy Awards, dedicated it to Karen Matthews, who had very recently been found guilty of kidnapping Shannon Matthews, her own daughter. Carr was quoted by BBC News as stating: "I should dedicate this award to her [Karen]. She would be my dream guest. I think she's a gay icon. People like a bit of rough, don't they?"
Shahid Malik, MP for Matthews' constituency of Dewsbury described Carr's comments about Shannon Matthews as "sick and insensitive". Carr subsequently apologised for his comments, saying "I realise what I said was insensitive and I am very sorry for any offence caused". On his own website he added: "For those of you who have enjoyed my comedy and seen my act over the last seven years you all would have got used to my tongue in cheek style and near the knuckle observations. Last night at the Comedy Awards [...] I was being ironic, these aren't my real sentiments obviously".