[2][3] His father worked as a sheep shearer in rural South Australia outside a small township of Padthaway on the Limestone Coast.

[4] His family also lived in North Queensland, where Clarke completed his secondary schooling at Ignatius Park College.

[8] He also played Detective Jarek Wysocki in the 2011 Fox series The Chicago Code[9] and CIA interrogator Dan in the 2012 film Zero Dark Thirty.

In 2015's Terminator Genisys, Clarke portrayed John Connor,[12] and the film grossed over $440 million worldwide.

In 2023 he portrayed Roger Robb in Christopher Nolan's historical epic Oppenheimer and Lieutenant Barney Greenwald in William Friedkin's The Caine Mutiny Court-Martial.