He was educated at Collyer’s School and the University of East Anglia, where he earned a degree in English & American Studies.
Cummings played on the next two Del Amitri albums, Change Everything in 1992 and Twisted in 1995, as well as on various tours, including an appearance at Woodstock '94.
However, at the end of their United States tour of 1995, which saw them riding on the crest of a top ten hit there with the song Roll to Me, Cummings decided to leave the band.
As well as continuing to write for The Fast Show until its conclusion in 2000, Cummings co-wrote with Whitehouse the sitcom Happiness (BBC Two, 2000–01) and the feature film Kevin and Perry Go Large, which was a spin-off from Harry Enfield and Chums.
In 2015, he helped co-write Paul Whitehouse's sitcom Nurse, based on his Radio 4 show of the same name, which debuted on BBC 2 on 10 March.