[2] He was raised mainly in Surrey, and picked up an interest in acting after being spotted by a drama teacher at the comprehensive school he was attending.

[3] Between 1968 and 1972, Keays-Byrne had parts in Royal Shakespeare Company productions including As You Like It, The Balcony, King Lear,[4] Hamlet,[5] Much Ado About Nothing,[6] A Midsummer Night's Dream, The Tempest or The Enchanted Island, Doctor Faustus, The Man of Mode, Troilus and Cressida, Enemies, The Revenger's Tragedy, and Bartholomew Fair.

[8] He was part of Peter Brook's production of A Midsummer Night's Dream with the Royal Shakespeare Company, which toured Australia in 1973.

[9][10] After his first starring role in the TV film Death Train,[11] Keays-Byrne was cast as the violent gang leader Toecutter in Mad Max.

[1] Director George Miller had Keays-Byrne and the other actors for the gang travel from Sydney to Melbourne in a group on motorcycles, as there was no money for airplane tickets.

[12] Keays-Byrne then continued to act in post-apocalyptic and science fiction films such as The Chain Reaction, Strikebound,[13] Starship[14] and The Blood of Heroes.