Born in Glasgow, Scotland and raised by his parents in East Kilbride, his mother was a midwife and his father was a Royal Air Force Police mechanic and later a chief lecturer and engineer in prosthetics and orthotics. At a young age he started lifting weights and became a competitive junior Scottish bodybuilder, winning several championships in his late teens.He enrolled in evening acting classes part time before enrolling drama school in Glasgow. Shortly after he started work in the theatre, touring with Harold Pinter's classic, 'The Birthday Party', in the role of the menacing McCann followed by Jerry in Edward Albee's 'A Zoo Story', and Tambo in the world premiere of 'The Ringer', to rave reviews.He soon progressed to numerous T.V and film roles and making his own short films, notably Scene. (2006) playing a hapless actor trapped in a movie within a movie, for which he won his first BAFTA Scotland Award. A variety of diverse roles followed in American and British independent films, depression-era caper/heist The Red Machine (2009) then the self-penned Running in Traffic (2009) as the grief-stricken, drug dealing, Cullen, alongside Kenneth Cranham for which he won his second BAFTA and Trailblazer awards. He demonstrated his leading man versatility in the action heist Battleground (2012) and then again as the aged Bruce Callaghan in To Our Bright White Hearts (2016) before gaining over 40 lbs of muscle for the towering Russian, Dolokhov in Outpost: Rise of the Spetsnaz (2013)His career has been marked by playing on the duality of vulnerable but tough types, bringing a depth and complexity to otherwise two-dimensional characters. Let Us Prey (2014) as the brutal but broken cop Jack Warnock opposite Liam Cunningham and for Starz Outlander (2014).He appeared opposite Ciarán Hinds and Douglas Henshall in Shetland (2013) He was cast in his first Hollywood movie with Gerard Butler in London Has Fallen (2016) as SAS Lieutenant Will Davies. He caught to attention of casting director Mike Leeder and Donnie Yen and was chosen to play the lead antagonist, Ernest Hunter opposite Yen and Andy Lau in the gangster epic Chasing the Dragon (2017)Inspired by Hong Kong's landscape and energy, he created the hitman trilogy Dead End (2017) winning over 50 international film festival awards.He has made his mark in AAA video games and full body motion capture, including Blood & Truth (2019) and Horizon Zero Dawn (2017) Horizon Forbidden West (2022) and Final Fantasy XVI (2023)Also 2021 he appeared as Wiglaf in season finale of Vikings (2013) and the Black Mirror styled Everything was fine (2021) set entirely in a single hotel room Larkin shot and directed the entire film himself and acted six different versions of the same character losing their mind while alone in quarantine.
