Pegg was born as Simon John Beckingham in Gloucester, England, the son of Gillian Rosemary (Smith), a civil servant, and John Henry Beckingham, a jazz musician and keyboard salesman. His parents divorced when he was seven. He attended Stratford Upon Avon College to study English Literature and Performance Studies. Pegg later studied drama at the University of Bristol and wrote his undergraduate thesis on "A Marxist overview of popular Seventies cinema and hegemonic discourses".

In 1993 he moved to London and gigged on the stand-up comedy circuit before breaking into television comedy in Asylum, Six Pairs of Pants, Faith in the Future, Big Train and Hippies. From 1998 to 2004, Pegg regularly featured on BBC Radio 4's The 99p Challenge. In 1999, he created and co-wrote the Channel 4 sitcom Spaced with Jessica Hynes. For this project Pegg brought in Frost, his best friend. For his performance in this series, Pegg was nominated for a British Comedy Award as Best Male Comedy Newcomer. Pegg co-wrote (with Spaced director Edgar Wright) and starred in the "romantic zombie comedy" film (or "RomZomCom") Shaun of the Dead, released in April 2004. At George A. Romero's invitation, Pegg and Wright made cameo appearances in Romero's latest zombie film, Land of the Dead. In 2004 Pegg also starred in a spin-off of the television show Danger! 50,000 Volts! called Danger! 50,000 Zombies!, in which he played a Zombie Hunter named Dr Russel Fell.

Pegg's other credits include the World War II miniseries Band of Brothers, guest appearances on Black Books, Brass Eye Special, I'm Alan Partridge , The Parole Officer and in the Factory Records story 24 Hour Party People. He also played the mutant bounty hunter Johnny Alpha, the Strontium Dog, in a series of Big Finish Productions audio plays based on the character from British comic 2000 AD and featured in Guest House Paradiso, a film based on the sitcom Bottom, where he played a guest at Richie and Eddie's hotel.

Pegg appeared in the Big Finish Productions Doctor Who audio story Invaders From Mars as Don Chaney, and portrayed the Editor in the 2005 Doctor Who episode "The Long Game". He also narrated the first series of the documentary series Doctor Who Confidential.

Pegg auditioned for a part in the romantic comedy Love Actually, but the role eventually went to Rowan Atkinson. Upon completion of Shaun of the Dead, Pegg was questioned on whether he would be abandoning the British film industry for bigger and better things, to which he replied "It's not like I'm going to run off and do Mission: Impossible III!" which he then promptly went on to do, playing Benji Dunn, an I.M.F. technician who assists Tom Cruise's character, Ethan Hunt. In 2006 he played an American character, Gus, in Big Nothing alongside David Schwimmer.

In 2006, Pegg and Wright completed their second film, Hot Fuzz, released in February 2007. The film is a police-action movie homage and also stars Nick Frost. Pegg plays Nicholas Angel, a London policeman who is transferred to rural Sandford, where grisly events take place.

During 2007 Pegg has also starred in The Good Night (directed by Jake Paltrow) and Run, Fat Boy, Run directed by David Schwimmer and co-starring Thandie Newton and Hank Azaria.

Pegg confirmed in an interview on Friday Night with Jonathan Ross that he will be co-writing and starring in another film with Edgar Wright and Nick Frost. The title and content are yet to be confirmed but Pegg claimed it would be "the concluding part in what we are calling our 'Blood and Ice Cream' trilogy" (the first two being Shaun of the Dead and Hot Fuzz).

In those movies and in Spaced, Pegg typically plays the leading hero while Nick Frost plays the sidekick. However, he has revealed that their new movie Paul will reverse this dynamic. He also cast doubt on whether Edgar Wright would direct or not.

In its October 12, 2007 issue, Variety reported that Pegg will play the part of engineer Montgomery "Scotty" Scott in the film Star Trek, due to be released in 2008.

--Wikipedia