The koala named Lewis was given water and wrapped in a blanket after being found on a road in the New South Wales state town of Wauchope.
Rescuer Toni Doherty told Network Nine it was her “natural instinct” to rescue the koala from the fire.
She said she “immediately thought just get to him, put the fire out”.
The 14-year-old animal was taken to the nearby Port Macquarie Koala Hospital for treatment for severe burns to his feet, chest and stomach.
The hospital commented on its Facebook page: "She (Ms Doherty) is an absolute legend for capturing this male koala who was so disorientated by the flames and unfortunately was burnt further as he headed back into active fire.
"He has been treated and is now in the five-star accommodation at the Koala Hospital."
Wildfires in South Australia and New South Wales have prompted fire officials to issue emergency warnings.