He is the older brother of Gaz Coombes and was the newest member of Supergrass, officially joining in 2002, though he had been an unofficial member for the majority of the band's career to that point. He played keyboards on all of the bands' albums and tours, and helped with the writing and arranging. He favoured the Hammond organ, where his playing was described as "the perfect foil to Gaz's guitar bombast".
He lives in Oxford with his three children, Lila, Louis, Ailla. He has a second younger brother, Charly, who was keyboard player in 22-20s.