Jemaine Clement was born on 10 January 1974 in Masterton, New Zealand, and was raised by his Māori mother, in the Wairarapa region. He attended Makoura College in Masterton. After graduation, he moved to New Zealand's capital Wellington, where he studied drama and film at Victoria University of Wellington. There he met Taika Waititi (a.k.a. Taika Cohen) with whom he went on to form So You're a Man and The Humourbeasts. In 2004, the Humourbeasts toured New Zealand in a stage show titled The Untold Tales of Maui, a rework of the traditional Maori legends of Māui. The duo received New Zealand's highest comedy honour, the Billy T Award.
Clement and Bret McKenzie formed Flight of the Conchords while at Victoria University. They have toured internationally and released four CDs: Folk the World Tour in 2002, The Distant Future EP in 2007 (winner of 2008 Grammy for Best Comedy Album), Flight of the Conchords in 2008 and I Told You I Was Freaky in 2009. In 2005 the Conchords produced Flight of the Conchords, a six-part comedy radio programme on BBC Radio 2. They appeared on Late Night with Conan O'Brien, the Late Show with David Letterman and The Late Late Show. After appearing in 2005 on HBO's One Night Stand, the Conchords were offered their own 12-part HBO series Flight of the Conchords, which was based on their earlier BBC radio series of the same name. Its first season ran from June to September 2007, and was renewed for a second season, which aired on HBO in the US from January to March 2009. In December 2009, the Conchords announced the show would not have a third season.
Clement has appeared in several feature films. His debut was in the kung fu comedy Tongan Ninja, directed by New Zealander Jason Stutter. He has worked with Stutter on two more movies to date: the low budget ghost comedy Diagnosis Death and the drama Predicament, based on the book by late New Zealand novelist Ronald Hugh Morrieson. He was also the voice of Swayzak in the Toonami Shockwave game "Trapped in Hyperspace". Clement also has a role in American comedy Gentlemen Broncos, directed by Napoleon Dynamite's Jared Hess. This role landed him a nomination for the Independent Spirit Award for Best Supporting Male. Though Gentlemen Broncos was almost universally panned by critics, some singled out Clement's performance for praise. In 2010, he voiced Jerry in Despicable Me and appeared in the film Dinner for Schmucks. In 2011, he voiced Nigel in Rio, and in 2012 he appeared as the primary antagonist Boris the Animal in Men in Black 3. In 2012, Jemaine co-wrote, co-directed, and starred in a vampire mockumentary titled What We Do in the Shadows with Taika Waititi. It premiered at the Sundance Film Festival on 19 January 2014. He also reprised his role as Nigel in Rio 2.
Clement has starred in television commercials internationally and provided voiceovers for many others in New Zealand. On 5 February 2006, Outback Steakhouse began running a series of television commercials starring Clement during Super Bowl XL in which Clement pretends to be Australian and feigns an Australian accent. One of the long-running gags of Flight of the Conchords is the traditional rivalry between New Zealand and Australia and the differences between their accents. The campaign ended in July 2006.
Clement has been involved in award-winning radio work. In 1999, Clement was a Radio Awards Winner as writer for Trashed, for Channel Z, Wellington. In 2000, he was given a Special Radio Awards Commendation for The Sunglass Store.
Besides his television work on Flight of the Conchords, Clement was a writer and cast member of the television shows Skitz and Tellylaughs in New Zealand. Clement, with fellow Conchord member Bret McKenzie, guest starred as a pair of camp counselors in "Elementary School Musical", the season premiere of the 22nd season of The Simpsons, which aired on 26 September 2010.
Clement also played the role of a prisoner in a Russian 'Gulag' in the 2014 film, 'The Muppets - Most Wanted', a sequel to 'The Muppets' (2011)
Clement was featured as one of 2008's "100 Sexiest People" in a special edition of the Australian magazine Who. Fellow Conchord member McKenzie appeared on the same list.
In 2015, Clement voiced a horse in two DirecTV commercials. In the same year, he voiced a "mind-reading fart" on an episode of the Adult Swim animated series Rick And Morty, where he performed the song "Goodbye Moonmen". Clement also starred in the independent film, People Places Things, which received positive reviews.
In 2016, Clement lent his voice to Tamatoa, a giant coconut crab, in the Disney animated film Moana. He based the character's voice on that of David Bowie.
In 2017, Clement played Oliver Bird in the FX TV series Legion. He also playes Sauron in The Lego Batman Movie.
In August 2008, Clement married his longtime girlfriend, theatre actress and playwright Miranda Manasiadis. Their first child, a son named Sophocles Iraia Clement, was born in October 2008, in New York City.