Barry made his acting debut in 2000, with the role of ‘Ivan’ in the ‘NBC’ film 'In His Life: The John Lennon Story,' focusing on the teenage life of singer, songwriter, and peace activist John Lennon. He waited for 2 years to receive his breakthrough TV role until he was booked for the part of ‘Sean Smith’ in the 'Channel 4' soap opera 'Brookside' (2002–2003, 65 episodes).
He appeared in the TV movies: 'Pleasureland' (as ‘Darren’) and ‘I'm a Juvenile Delinquent – Jail Me!' (as ‘Piers’). In 2004, Barry appeared in the 'BBC One' medical drama 'Holby City,' as ‘Kevin Sharpe.’ He later made a recurring appearance as ‘Kieran Callaghan’ in eight episodes of the show (2010–2011).
Barry is credited as the lead character, ‘Glynn,’ in the 2007 ‘BAFTA'-winning TV movie 'The Mark of Cain.' His next TV project was the long, recurring character (90 episodes) of ‘Niall Rafferty,’ a mysterious hairdresser, in the 'Channel 4' soap opera 'Hollyoaks' (2007–2008). He reprised the role in four episodes of the spin-off, 'Hollyoaks Later' (2008).
His remarkable performance as the antagonist ‘Niall Rafferty’ earned him a 'National Television Award’ nomination for the ‘Most Popular Newcomer’ in 2008 and two ‘British Soap Award’ nominations for the ‘Villain of the Year,’ one each in 2008 and 2009.
Barry appeared as ‘Jackie Wray’ in two episodes of the 'ITV' crime drama 'DCI Banks' (2010), followed by the leading role (43 episodes) in the 'ABC' drama 'Revenge.'
In 'Revenge,' he essayed the character ‘Aiden Mathis,’ who was shot at the end of the second season but returned in season 3, revealing that he had survived a gunshot wound from ‘Daniel Edward Grayson’ (played by Josh Bowman). The character continued to help his love interest, ‘Emily Thorne’ (played by Emily VanCamp) in her revenge against the ‘Graysons.’ Barry's character departed in the season-3 finale, when ‘Victoria Grayson’ (played by Madeleine Stowe), Daniel's mother, killed him.
While juggling with his film and TV projects, Barry took up the role of ‘Troy Whitworth,’ a local thug who sexually abuses his stepdaughter, in Jez Butterworth's play 'Jerusalem,' which opened at the 'Jerwood Theatre' of the 'Royal Court Theatre,' London, in 2009. The show later transferred to the 'Apollo Theatre' in 2010 and then debuted on ‘Broadway’ at the 'Music Box Theatre' in the summer of 2011.
Barry had previously made his ‘West End’ debut with Willy Russell's 'Blood Brothers' in 2005.
He starred as ‘Chad’ in the 2013 thriller feature 'Penthouse North' (also known as 'Blindsided') and played a brief role of a poacher leader in the 2014 epic biblical drama film 'Noah.'
In 2015, Barry was seen as ‘Wes Lawrence’ (13 episodes), a high-ranking ‘Defense Department’ operative, the head of the ‘Special Projects Division’ at the ‘DOD,’ and the former assistant director of the ‘FBI,’ in the 'ABC' science-fiction drama 'The Whispers.'
Barry played ‘Zachary "Zach" Heflin,’ a deputy and the love interest of ‘Cady Longmire’ (played by Cassidy Freeman), in the fourth season of the 'A&E' Western crime drama 'Longmire.' He continued till season 6 (10 episodes, 2015–2017).
He portrayed Separatist Edward Winslow, who had traveled on the English ship 'Mayflower' in 1620, in the 'National Geographic Channel' two-part miniseries 'Saints & Strangers' (2015), which was about the 'Mayflower' voyage.
Barry starred as the lead, ‘Senior Chief Special Warfare Operator Joe "Bear" Graves,’ in the 'History' drama 'Six' (2017–2018). In 2019, he played the recurring role of ‘Dante Sherman’ in the 'Spectrum Originals' police-procedural drama 'L.A.'s Finest' and voiced the video-game character ‘Captain Price’ in 'Call of Duty: Modern Warfare.'
Barry was seen as ‘Jake Reilly’ in the 'NBC' legal drama 'Bluff City Law.' The pilot episode of 'Bluff City Law’ was aired on September 23, 2019. He is represented by Jeff Golenberg of 'Silver Lining Entertainment' and Ken Lee of 'Innovative Artists.'
He worked as an executive producer for the 2016 short ‘Shooting an Elephant.’