Watson has appeared regularly at the Edinburgh Festival Fringe, winning the first ever Panel Prize at the if.comeddies in 2006 and being nominated for Best Newcomer at the 2005 Perrier Comedy Awards.

These shows have featured guest appearances from other performers such as Tim Minchin, Adam Hills, Daniel Kitson, David O'Doherty, Sarah Millican,[9] Gillian Anderson,[10] and John Dorney as the balladeer.

The aim was to write, by the end of August, a novel begun from scratch and woven entirely from audience suggestions, with another 2,000 words or so added each day.

We Need Answers returned in 2008 with fewer rounds, Josie Long emerged as winner, beating Sinha in the semi-final and Kristen Schaal in the final.

In 2019, Watson staged a 26.2-hour live show to coincide with the London Marathon, and during the COVID-19 pandemic in 2020 he hosted two 24-hour "Watsonathon" events on the Twitch streaming platform.

[12] Watson often performs gigs in unusual locations including: on a ferry,[13] from a stream,[14] on a train,[15] on the steps outside a theatre,[16] in a vaccination queue,[17] and in drive-in shows during the Covid pandemic.

[22] In 2012, Watson starred with Micky Flanagan and host Mark Dolan as a captain in the Channel 4 panel programme The Mad Bad Ad Show.

[23] Watson has appeared as a panellist on shows including Never Mind the Buzzcocks, QI, Who Said That?, Guessable, 8 Out of 10 Cats, Argumental, Have I Got News For You, Mock The Week, Would I Lie to You?

In Australia, Watson has been seen on Rove, Good News Week, Spicks and Specks and the Melbourne International Comedy Festival, all aired in April 2007.

In 2017, he competed in series 5 of Taskmaster against Bob Mortimer, Sally Phillips, Nish Kumar and Aisling Bea, finishing joint second.

[31] In December 2021, Watson launched a podcast through his production company with co-host Michael Chakraverty called menkind, discussing masculinity with a weekly guest.

In 2020 during the COVID-19 pandemic, Watson, Tim Key and Alex Horne started a YouTube channel playing a game known as No More Jockeys.

[33] In 2009, Watson appeared in adverts for Magners Pear Cider, which became the subject of an extended routine by fellow comic Stewart Lee as part of his 2009, "If You Prefer A Milder Comedian, Please Ask For One" live show.

Watson proposed to Emily Howes, a fellow novelist, writer-performer and theatre director during a live marathon comedy routine at the Fringe, in front of an audience of 200.