He has made various appearances on British science fiction shows including Red Dwarf and multiple roles on Doctor Who - most notably with his 2020 portrayal of computer pioneer Charles Babbage.
Between October 2008 and January 2009, Mark Dexter made regular appearances on NBC in America, playing the role of Samuel Tuffley in eight episodes of Crusoe, a major 12-part mini-series.
On 3 March 2013, Dexter portrayed the celebrated polar explorer Ernest Shackleton in episode 9 of the ITV series Mr Selfridge, and later that year he appeared as CIA Agent 'Marlow' in 24: Live Another Day, which was broadcast in the US and UK in spring 2014.
In October 2014, it was announced that Dexter would portray British Prime Minister David Cameron in political drama Coalition, a film for Channel 4 set to be broadcast in the run-up to the UK general election in 2015.
[11] Dexter was cast as SS Commander 'Dietrich' in the WWII drama The Exception directed by David Leveaux, which had special screenings at the Toronto and Tribeca film festivals (September 2016 & April 2017), ahead of its general release in June 2017.