Prior to filming, Ben Mendelsohn and Luke Ford made a conscious decision not to speak to each other as actors to help with their portrayal of two antagonistic brothers.
This was the major film debut for both male lead James Frecheville and his on-screen girl friend played by Laura Wheelwright.
When David Michôd was writing the part of Detective Nathan Leckie - who he envisioned as being slightly anachronistic, an old-fashioned cop in a modern world - he had the idea of Leckie wearing a mustache. When he spoke to Guy Pearce about the part, he was quite surprised when Pearce suggested that the character should sport a mustache.
Writer/director David Michôd said he often relented to Ben Mendelsohn's request for additional takes of his scenes because his respect for the actor's 'wild, unpredictable' contributions. In fact, the very first scene featuring Mendolsohn's 'Pope' character took about 15 takes.
David Michôd explained that among the unplanned, unscripted elements he felt compelled to add to the film's opening moments for clarity, after shooting was complete, were the stills montage of bank robberies and the voiceover by protagonist Josh/J.