Daryl Montague, a father from South Australia, died in hospital after the car he was driving with his son, Jaxson, and his girlfriend, Ashanti Smith, crashed on December 27 in the Mid North.
The car had been traveling on the wrong side of the road.
The three were on their way to Port Pirie from Augusta when the car left the road at around 7:30 pm.
The teenagers died on the scene, while Daryl was taken to the hospital in critical condition.
On Sunday, police confirmed that Daryl died.
Logan Montague, the son of the 46-year-old, paid tribute to his father on social media.