He first entered the music scene aged sixteen as the lead singer of the band The Jennifers which featured Supergrass band mate Danny Goffey. Coombes was noticeable for his large sideburns during the 1990s.
The band released six studio albums in their 17 years together, each of them entering the UK top 20: I Should Coco (1995), In It for the Money (1997), Supergrass (1999), Life on Other Planets (2002), Road to Rouen (2005) and Diamond Hoo Ha (2008). They also released a singles compilation Supergrass is 10 (2004), commemorating the first decade of the band’s life.
On 12 April 2010 Coombes and the rest of Supergrass announced that the band was to split after seventeen years. Musical differences were cited as the reason. They played four farewell concerts before the split. Their seventh album Release the Drones remains unfinished and unreleased.
Coombes’s second solo album, Matador, was released on 26 January 2015. The album debuted at number 18 in the Official UK Album chart.