"Be proud but understand what you're being proud of.
"I stand for us, our mob! Be proud of the oldest living culture.
"Always was, always will be."
Mitchell is a proud Indigenous man and appeared in this year's NRL marketing campaign with the Aboriginal flag draped across his back.
During last year's State of Origin series, the NSW centre made headlines when he protested against the anthem by refusing to sing, as did Blues teammates Cody Walker, Josh Addo-Carr and Blake Ferguson.
Mitchell didn't play in this year's Origin series but the anthem protests from players continued.
The South Sydney fullback may not have loved the national anthem on Saturday night but plenty of others did.
The Daily Telegraph's Jamie Pandaram posted on Twitter: "Absolutely fantastic: every Wallabies player sung the first half of the national anthem in Indigenous language. Learned the words. Paid respect. A great step forward."
Rugby Australia reporter Christy Doran also called the spectacle "spine-tingling".
"The finest rendition of the Australian national anthem. That was brilliant. Never felt more proud of our anthem. Well done Olivia Fox," he posted on Twitter.
The Wallabies' official Twitter profile called it a "goosebumps" moment while Australian Paralympic legend Richard Coleman wrote: "That is one incredible national anthem @wallabies! As an athlete every time the Australian anthem is performed it should be done this way. I would love to win a gold medal and hear this playing loud and proud, so inspiring."
It was reported this week the Wallabies playing group had been learning the lyrics in Eora to show the team is serious about recognising the role of First Nations people in the sport.