His works include "1912: The History of Antarctica", "Stranger Than Fiction for Lonely Planet" and "The Rosie Project" as well as multiple audiobook works for the RNIB. In late 2009, Millar – along with his Creative Director – generated a comedic video audition for the role of Mary Poppins in "Mary Poppins The Musical", and posted it on YouTube. Following a viral online reception and a second video, filmed in New York, Millar was invited to perform as Mary live onstage at Hats Off 2010 at the Seymour Centre. Millar then went on to create a second video discussing his attempt to be cast as Sandy (the dog) in an upcoming production of "Annie"  In 2005, Millar won the inaugural Cabaret Showcase in Sydney. In 2006, Millar won the Green Room Award for Best Supporting Actor in 2006 for his performance of Jud Fry in "Oklahoma!" in Melbourne. In 2008, Millar won best actor in the Sydney "Short and Sweet" Festival for his performance in the short play "Blenderman". In 2009, "LoveBites" was nominated for best cabaret at the Sydney Theatre Awards and "The Hatpin" was nominated for best new Australian work. In 2010, Millar was nominated for a Sydney Theatre Award, a GLUG and a Green Room Award for his performance of "Doug Simon" in Gutenberg! The Musical!. In 2014, "A Little Touch of Chaos" won the Arts Victoria Grant for best New Australian Work. In 2016, Millar won the Helpmann Award for Best Male Actor in a Musical for his performance as Miss Trunchbull in Matilda the Musical.