He was part of the alternative comedy boom in the early 1980s and had roles in the television series The Young Ones (1982–1984) and Bottom (1991–1995), which he wrote together with his collaborator Rik Mayall.

For two episodes of this he created the spoof heavy metal band Bad News, and for another he played his nihilistic alter-ego Eddie Monsoon, an offensive South African television star.

In the 2000s, Edmondson appeared in numerous TV programmes in drama roles including Jonathan Creek, Holby City, Miss Austen Regrets, as himself on Hell's Kitchen and created the sitcom Teenage Kicks.

In 2013, Edmondson was crowned the winner of Celebrity Masterchef, and from 2019 to 2020, he appeared in the BBC soap opera EastEnders as Daniel Cook.

As a child, Edmondson lived with his family in a variety of places including Cyprus, Bahrain, and Uganda, where his father was a teacher in the British Armed Forces.

By the time he was in sixth form, with his parents working abroad, Edmondson began to enjoy himself, "which involved lots of drinking and smoking and petty acts of vandalism."

As their popularity grew, Edmondson, Mayall and other upcoming comedians, including Nigel Planer, Peter Richardson, Alexei Sayle, and French and Saunders moved from the Comedy Store to The Comic Strip club.

The first episode to be broadcast was "Five Go Mad in Dorset", a parody of Enid Blyton's Famous Five, which drew anger from some viewers for the way it mercilessly satirised a children's classic.

In 1983, he appeared as the lead singer "Vim Fuego" in the spoof heavy metal band called "Bad News" with his Young Ones co-stars Rik Mayall, Nigel Planer, and Peter Richardson of "Comic Strip Presents...".

[8] In 1987, Edmondson reunited with Planer and Mayall to star in Filthy Rich & Catflap, a comic attack on showbiz, again written by Elton.

In this show Edmondson displayed the same slapstick characteristics as Vyvyan in The Young Ones but was closer in personality to his later character "Eddie Hitler" in Bottom.

Edmondson played Brad Majors in the 1990 West End run of The Rocky Horror Show, alongside Tim McInnerny as Frank-N-Furter and Ed Tudor-Pole as Riff-Raff.

In an August 2010 edition of Radio 4's Chain Reaction programme he said to Lee Mack that he had not really quit[clarification needed] but was focusing more on music and farming.

Mayall appeared during Edmondson's winning performance of The Dying Swan on BBC One's Let's Dance for Comic Relief on 5 March 2011, and in September 2011, Edmondson appeared on the Sunday morning cooking show Something for the Weekend and told presenter Tim Lovejoy that he and Rik Mayall were planning to reunite and make another series of Bottom, set in an old people's home.

[12] He also presented the ITV series Ade in Britain that year, where he travelled to different parts of the United Kingdom in a Mini Countryman towing a small caravan, often including a performed segment from local folk singers.

A one-off special, Britain Beware, about the history of British public information films, was hosted by Edmondson and aired on ITV on 7 May 2012.

From 2 November to 3 December 2016 Edmondson starred in an adaptation of William Leith's bestseller Bits Of Me Are Falling Apart at the Soho Theatre, London.

[23] From September 2018 to November 2018, Edmondson toured with Nigel Planer in a play that they wrote together called Vulcan 7[24] (restaged in 2023 as It's Headed Straight Towards Us[25]).

[27] In 1986, Edmondson achieved a number one hit in the UK Singles Chart when he and his co-stars from The Young Ones teamed up with Cliff Richard to record a new version of "Living Doll" for the inaugural Comic Relief campaign.

Edmondson has directed pop videos for "Fiesta" (1988) by the Pogues, "Prime Mover" (1987) by Zodiac Mindwarp, "Like the Weather" (1988) by 10,000 Maniacs, "Please Help the Cause Against Loneliness" (1988) by Sandie Shaw and "Hourglass" by Squeeze (1987).

He also directed "Black Sheep Wall" (1989) by The Innocence Mission, "This Town" (1989) by Elvis Costello and "When I Grow Up" (1989) by Michelle Shocked.

[29] In 1991, Edmondson formed the Bum Notes, who were a jazz instrumental band and conceived exclusively to perform theme music for Bottom.

A fan of the Bonzo Dog Doo Dah Band, Edmondson performed vocals with them as part of their 2006 reformation and countrywide tour.

[30] Together with Maartin Allcock, Andy Dinan and Troy Donockley, Edmondson founded the band the Bad Shepherds in 2008, performing punk and new wave classics on traditional folk instruments.

[31] In 2010, he founded the Idiot Bastard Band with Simon Brint, Rowland Rivron, Neil Innes and Phill Jupitus.

His favourite song was "Wide Open Spaces" by The Dixie Chicks, his book choice was Waiting for Godot by Samuel Beckett, and his luxury item was a tab of acid.