Jonas Armstrong started his acting career on stage with the role of Derek Meadle in the play ‘Quartermaine's Terms’ at the Royal Theatre in Northampton in 2003. The following year, he played Henry in the play ‘The Skin of Our Teeth’ at the Young Vic Theatre in London and also made his television debut as series regular Anthony Millington in the fourth season of the British television comedy-drama ‘Teachers’ on Channel 4. In 2005, he played Richard in the play ‘Rutherford and Son’ at the Royal Exchange Theatre in Manchester. Also that year, he joined the cast of another Channel 4 series, the crime drama ‘The Ghost Squad’, as series regular Pete Maitland. Following an appearance on the two-part ITV crime drama miniseries ‘Losing Gemma’ (2006), he bagged the lead role of Robin Hood in the eponymous BBC television series that ran for 39 episodes spanning three seasons and earned him major recognition. During this period, he reprised the role in ‘Robin Hood Cinema Commercial’ (2006) and was a guest panelist on the BBC comedy panel game show ‘Never Mind the Buzzcocks’ (2007). He had already announced leaving ‘Robin Hood’ after third season in 2009, following which he made his film debut starring as Simon McNeal in the erotic horror mystery film ‘Book of Blood’ and made guest appearances in three episodes of the drama series ‘The Street’. Also in 2009, he read four stories for ‘The Bedtime Hour’ on ‘CBeebies Bedtime Story’.
In 2010, Jonas Armstrong had a single guest appearance in the episode ‘The Secret of Chimneys’ of the British television program ‘Agatha Christie's Marple’. The next year, he played supporting roles in two episodes of the thriller miniseries ‘The Field of Blood’, one episode of the crime drama miniseries ‘The Body Farm’, and appeared in the horror telefilm ‘Rage of the Yeti’, apart from starring opposite Lacey Turner in the drama film ‘Life Outside’. In 2012, he landed regular roles in the BBC drama series ‘Prisoners Wives’ and the Sky Atlantic miniseries ‘Hit & Miss’, and also appeared in the thriller film ‘Twenty8k’. Next in 2013, he played a major role in the telefilm ‘The Whale’ and starred alongside Sir Ben Kingsley in the American action drama film ‘Walking with the Enemy’, the latter earning him a ‘Stars on Horizon’ award at the ‘Fort Lauderdale International Film Festival’. He subsequently played a supporting role in the American science fiction action film ‘Edge of Tomorrow’ starring Tom Cruise and Emily Blunt. After another supporting role in the two-part American miniseries ‘The Dovekeepers’ (2015), he made guest appearances in three episodes of the third season of the British police procedural series ‘Line of Duty’, played the main role of Joe Nattrass in the two-part drama miniseries ‘Dark Angel’ and appeared as series regular Nathaniel Croker in fourth and fifth seasons of the mystery drama series ‘Ripper Street’, all in 2016.
Jonas Armstrong’s next big role was as Menelaus in the British-American fantasy action adventure miniseries ‘Troy: Fall of a City’ in 2018. He subsequently appeared in one episode each of the series ‘Urban Myths’ (2018) and ‘Death in Paradise’ (2019), and acted in the short film ‘Boiling Point’ (2019). Also in 2019, he played series regular Sean Meredith in the ITV crime drama series ‘The Bay’. Next year, he played the main role of Finn Coleman on the British horror series ‘Ghost Seekers’ and starred in the German action film ‘The Enemy’. In 2021, he portrayed the main role of Jason on the four-part Channel 5 thriller series ‘The Drowning’ and appeared as regular cast member Gareth Boyd on the ITV thriller series ‘Hollington Drive’. He recently acted in major roles in the short film ‘Leave to Remain’ and the feature film ‘Floodlights’ in 2022 and is scheduled to appear in the upcoming movies ‘Three Day Millionaire’ and ‘Look the Other Way and Run’.