[1] While studying in Perth, he was directed and tutored by a number of notable Australian performers such as David King, Tony Sheldon, Nick Enright, Roma Conway, Rhys McConnochie, Adam Cook, John Milson and Nancye Hayes.
[3] For television, Millar has played roles in Home and Away, Police Rescue, A Country Practice, The Leaving of Liverpool, The Investigators (ABC TV), Water Rats and Neil Armfield's tele-film Naked: Coral Island.
He joined Doctor Zhivago star Lucy Maunder in a production of Noel and Gertie, based on the diaries and letters of Noël Coward and Gertrude Lawrence.
[1] In 2013, he featured in the Australian premiere of Grey Gardens for The Production Company, The Ring Cycle at the Royal Opera House in London, and toured the UK in Chess as Molokov.
In April 2014, Millar was announced for the ensemble cast of the US arena tour of Jesus Christ Superstar, starring Ben Forster and John Lydon.
[9] In April 2015, it was announced that Millar would play Miss Trunchbull in the Australian premiere season of Matilda the Musical opening in Sydney in July.
In 2023, Millar was invited to direct Sweeney Todd: The Demon Barber of Fleet Street at the Elder Conservatorium in Adelaide, South Australia.
[1] In 2006 and 2007, Millar wrote and developed the musical The Hatpin alongside composer Peter Rutherford, based on a series of infanticides committed in Sydney by John and Sarah Makin (renamed Agatha and Charles for the show) in 1892, as well as the attempts by single mother Amber Murray to find justice for her son Horace.