They started TBA, which was billed as London's first sketch comedy club, and performed together at the Edinburgh Fringe seven times between 1993 and 2001. In 1998, they also performed in Sydney, Melbourne and Adelaide.

Like many writers, they cut their teeth on Radio 4's Week Ending, and were offered their own show, Parsons and Naylor’s Pull-Out Sections in 2001, which ran for nine series on Radio 2. In 2008, Parsons wrote and starred in his own Radio 4 sitcom, The Lost Weblog Of Scrooby Trevithick.

On TV, the pair also wrote for Spitting Image, Noel's House Party, Hale and Pace and Alas Smith And Jones, among others.

Parsons performed his first solo show at the Edinburgh Fringe in 2000, and returned regularly until 2006. He is a regular member of the Comedy Store topical show Cutting Edge and has appeared at the Montreal Just For Laughs comedy fesival in 2006; the New Zealand Laugh Fest in 2003, 2004 and 2006; and Cat Laughs, Kilkenny, in 2005.

He won a Time Out award for comedy in 2002, and was named best international act by the New Zealand Comedy Guild in 2004.

Apart from Mock The Week, his other TV credits include Live At The Apollo, QI, Live Floor Show, They Think It's All Over and the BBC's Stand-Up Show.