Queen Elizabeth has approved the posthumous awarding of Victoria Cross for Teddy Sheean, Governor-General David Hurley has confirmed.
His Excellency made the announcement at 2pm on Wednesday, describing it a momentous day for his family.
"In my conversations with them, their pride and emotions were evident," he said.
His Excellency said many had heard Ordinary Seaman Sheean's story for the first time and had been taken aback.
"His story is inspiring and should inspire us all," he said.
Ordinary Seaman was just 18 when he was onboard the HMAS Armidale when it was struck by Japanese enemy aircraft on December 1, 1942.
While the ship was sinking under sustained attack, he strapped himself to an Oerlikon anti-aircraft gun and fired at the bombers.
Two were damaged through the action.
This confirmation follows on from Prime Minister Scott Morrison's announcement on Monday that he had made the recommendation to Queen Elizabeth that Sheean be posthumously awarded the honour.
The Defence Honours and Awards Appeals Tribunal in May recommended Ordinary Seaman Sheean be awarded a VC after a 2019 inquiry.
The federal government refused the recommendation.