The Northern Territory Police said Phu Tran was found by a livestock farmer in a remote area south of Alice Springs and was taken to a hospital to be treated for exposure.
Police Superintendent Pauline Vicary said at a news conference that the 40-year-old survived after finding some groundwater.
"If you believe in miracles, I'm saying it's a miracle," she said Tuesday.
The trio set out from Alice Springs for an afternoon drive on Nov. 19 when their car got stuck in a riverbed in the arid region, according to police. On Sunday, officials announced they found 52-year-old Tamra McBeath-Riley near a waterhole where the group had been staying.
McBeath-Riley said during a Monday news conference that on Thursday her friends -- Claire Hockridge, 46, and Tran -- began the 12-mile journey to reach a nearby highway, planning to avoid the desert heat -- which came close to 104 Fahrenheit in recent days -- by walking at night and carrying whatever water they could find.
"We tried many times to try to get out, but just couldn't get out, so ventured forth to try and find some shelter and some water," she said. "The river was just too large, we couldn't get out."
During the day, the group dug a hole underneath the car to stay cool and then slept in the vehicle at night, the Australian Broadcasting Corporation reported. During that time period, the trio survived on six liters of water, 10 cans of iced vodka, a packet of biscuits and some beef noodles.
McBeath-Riley said she decided to stay at the waterhole with her Staffordshire terrier because she did not think the dog would survive a walk to the Stuart Highway, which connects Australia’s north and south coasts. The group did not know if anyone was looking for them.
Vicary told Australia's NT News that Tran and Hockridge separated after finding the fence on the farm property, and the 40-year-old decided to follow the fence line for two days until he was discovered by the farmer and given water.
She added that Tran was "slightly disoriented" when he was found but in good spirits.
Police said Monday that rescue efforts have "ramped up," with two helicopters covering 14 square miles from the Stuart Highway, the general area where it is believed Hockridge may be. Vicary said that so far searchers had only found one set of footprints.
"It's quite a diverse terrain," she told reporters. "There's sandy dunes, there's hard clay, there's areas of dense trees, but there are also rocks and ranges in the area."
The Associated Press contributed to this report.