As a youth, Champion's musical influences included Tom Waits, Nick Cave and traditional Irish folk music. He learned to play piano and violin when he was 8 and he learned to play the guitar when he was 12. He also has experience on the bass, and tin whistle. Before he joined Coldplay, Champion performed in a band called Fat Hamster.
Champion was the last of the four band members to join the ensemble on 31 July 1997. He took up the position as drummer with no prior experience, but quickly adjusted to fill the role. In 1999, lead singer Chris Martin sacked Champion, but the band asked him to return soon after.
In Coldplay, he is often regarded as the rationality of the group. They say of him: "Will does have a very sensible head on his shoulders and when it comes to making band decisions he's really good at putting valid points across and keeping everyone focused. He frequently has the casting vote and his decision can sometimes override the consensus!" As Chris Martin has said in multiple interviews, "We [Coldplay] are all just working for Will Champion."
During the Viva la Vida Tour, Champion sang and performed an acoustic version of the song "Death Will Never Conquer". A version of the song was included on Coldplay's live album LeftRightLeftRightLeft. He has also performed lead vocals on a live version of "Til Kingdom Come" and the Life in Technicolor II b-side "The Goldrush".
Champion's mother, Sara, a Doctor of Prehistoric Archaeology, died from cancer in 2000. The album Parachutes was dedicated to her.
Champion was the first Coldplay member to marry: He married Marianne Dark, a teacher, in 2003. Their first child, a girl named Ava, was born on 28 April 2006. On 7 May 2008, Marianne gave birth to fraternal twins Juno and Rex.
Champion currently uses a Yamaha drum kit with Zildjian cymbals. In the music video for "Christmas Lights", he uses a Slingerland drumkit and Ludwig Supraphonic Snare 14x6.5 inches. For sticks, Champion looks to Pro-Mark's American Hickory 5A stick with a wooden tip. He is known to use 4 or 5 pairs of these per show.