When he was three, Mayall and his parents moved to Redditch, Worcestershire, where he spent the rest of his childhood. He studied drama at Manchester University and gained fame by appearing at The Comedy Store in the Eighties along with Edmondson. They starred as "The Dangerous Brothers", supposedly a couple of naive but anarchic daredevils, and would perform comedy stunts on stage, often involving the likes of setting each other on fire. They effectively brought slapstick to the alternative comedy scene, albeit in a typically extreme fashion.
A role as Rik in The Young Onessitcom, also in the Eighties, ensured wide public acclaim. The series was written by Mayall with long-standing friend Ben Elton and Lise Mayer. Additional material was provided by anarchist comedian and actor Alexei Sayle. More recently Mayall has starred in Bottom, again with Adrian Edmondson (in which the two of them effectively reprised their roles in The Young Ones), although he also did solo work such as several series playing Conservative MP, Alan B'stard, in the sitcom The New Statesman. He has also appeared in films, notably Drop Dead Fred. He also appeared in Blackadder series 2 and 4 as Lord Flashheart.
In 1998 he was seriously injured when he crashed a quad bike near his home in Devon, although he later made a full recovery.
Mayall has also played the role of Professor Adonis Cnut in the sitcom Believe Nothing.
In a 2005 poll to find The Comedian's Comedian, he was voted amongst the top 50 comedy acts ever by fellow comedians and comedy insiders.
When he was three, Mayall and his parents - both of whom taught drama - moved to Redditch, Worcestershire, where he spent the rest of his childhood and performed in his parents' plays.
In 1986, Mayall achieved a #1 hit in the UK singles charts when he and his co-stars from The Young Ones teamed up with Cliff Richard to record a new (and somewhat offbeat) version of Living Doll for the inaugural Comic Relief campaign.
Mayall has also played the role of Professor Adonis Cnut in the sitcom Believe Nothing and was Peeves the poltergeist in the first Harry Potter movie (Harry Potter and the Philosopher's Stone) but was cut out of the final edit.