Television

Clarke presented ITV's long running children's television show SMTV Live from March to December 2003, following the departure of Ant & Dec.^[9] He has hosted Whatever on Sky One, Discovery's Invention SOS and Club Cupid, the adult dating show on STV as well as fronting the Scottish coverage of Children in Need.^[10] Clarke has also been involved in sports broadcasting, appearing regularly on BBC One Scotland’s flagship football programmes, Offside and Sportscene as well as Sportsround on the CBBC Channel. At the end of 2007, Clarke hosted From SR to Lavvie Heid: How We Made the Break, an affectionate look at the top 50 adverts shown in Scotland since 1957 as part of the celebrations for STV's 50th birthday.

Clarke has also appeared in BBC One's Live Floor Show and BBC Two's World Cup's Most Shocking Moments.^[11] In 2014, Clarke was a panelist on CBBC's The Dog Ate My Homework. He is also a regular warm-up comedian for BBC Scotland. Clarke hosted the closing ceremony of the 2014 Commonwealth Games.^[9] In 2019, Clarke made a guest appearance in the first episode of the ninth series of Still Game. Clarke is the announcer for the 2024 British version of Jeopardy!.

Radio

Clarke spent three years as a DJ on Scottish radio station Beat 106, fronting the Breakfast Show and winning the Presenter of the Year at the British Radio Awards in 2004.^{[citation needed]} Clarke later returned to Beat 106 under its new name of Xfm Scotland. On 7 November 2008, Xfm Scotland became Galaxy Scotland and on 10 November 2008, Clarke began hosting a weekday breakfast show with Vanessa Motion, Des & Vanessa @ Breakfast. On 3 January 2011, Galaxy Scotland was renamed and rebranded as Capital Scotland, where he became a breakfast co-presenter alongside Jennie Cook,^[12] and later Steven Mill and Amy Irons.^[13] He left Capital Breakfast after Global Radio announced that Heart, Capital, and Smooth would be moving to all National Breakfast shows.

In 2015, Clarke began presenting the topical quiz show Breaking the News on Radio Scotland.^[14]

In March 2019, it was announced that Clarke would be moving to Heart Scotland as part of a reshuffle at Global Radio.^[15] Clarke presents the Heart Scotland Drivetime Show weekdays from 4pm–7pm alongside Jennifer Reoch.^[16]

In April 2023, Global announced a refreshed schedule for Heart Scotland and its sister station Capital Scotland. Des & Jennifer were confirmed to be new hosts of Heart Breakfast with Des & Jennifer weekdays from 6:30am. Broadcasting LIVE from Glasgow to Scottish listeners, moving away from Heart Breakfast with Jamie & Amanda, which continues to broadcast to the rest of the UK. The new schedule for Scotland started on 2nd May.^[17][18]

Comedy

Clarke is a regular performer on the comedy circuit, playing venues such as The Stand, The Comedy Store and Jongleurs. Clarke has performed at the Edinburgh Festival Fringe since 2001 and the Glasgow International Comedy Festival. Clarke has also made appearances at the New York, Adelaide, Dubai and Dublin Comedy Festivals.

Theatre

In 2012, Clarke starred as the lead comic role, Buttons, in Cinderella, at the King's Theatre in Glasgow. He starred alongside Karen Dunbar as The Fairy Godmother and Gavin Mitchell as an Ugly Sister. He has been a regular Panto veteran at the King's Theatre starring alongside the likes of Gregor Fisher, Tony Roper, Greg McHugh and Juliet Cadzow.