Born in Middlesex, Munnery grew up in Bedmond[1] and was educated at Watford Grammar School for Boys, where he earned four A Levels.

His most famous title was a version of Asteroids for the Commodore International VIC-20 (a game that Jeff Minter once described as a "pile of wank").

While at university, Munnery took part in a stand-up double-act called God and Jesus with Stephen Cheeke.

He also worked (along with Steve Coogan, Patrick Marber, Richard Herring and Stewart Lee) at the Edinburgh Festival in a piece called The Dum Show.

His reoccurring 2004-09 Edinburgh Fringe show, AGM, included the opportunity for the audience to raise questions to discuss as group (such as "is there a God?").

As well as Simon Munnery, it included Kombat Opera Presents (Loré Lixenberg and Richard Thomas) and a selection of pop videos.

It starred Munnery as 'The League Against Tedium', a character who drove around the United Kingdom in an adapted transit van, preaching to the masses with the help of an opera singer (Loré Lixenberg), a sedated vampire (Richard Thomas), and a monkey (Munnery's wife Janet).

Munnery has several CDs available: Alan Parker – Blast From The Past (featuring Stewart Lee on guitar and Al Murray on drums), Simon Munnery's Experimental Half Hour (2 CDs from the Resonance FM radio show of the same name), AGM recorded live at the Edinburgh Fringe Festival 2003, and BucketHead: Phenomenon Anon And On and Mr Bartlett & Mr Willis (2011) written and co-performed by Kevin Eldon.

Two DVDs of his work were released in 2007 – the first IAMTV, covering his Perrier Award nominated show from the 1999 Edinburgh Fringe, was closely followed by Hello produced by Go Faster Stripe, a more recent stand-up performance.

In 2009, Munnery starred in an award-winning animated rotoscope short, titled Yellow Belly End, co-written and directed by Philip Bacon, a student of the National Film and Television School.