The lawyer for Turia Pitt, who was badly burned on more than 60% of her body, said she was "very relieved".
Ms Pitt, a former model and engineer, became trapped in a blaze during the 100km (62 mile) race in the Kimberley region of Western Australia in 2011.
An official inquiry blamed race organisers for numerous failings.
The event sent runners through the El Questro Wilderness Park, where it was known that fires were burning.
The organisers, Racing the Planet, could have altered the course or cancelled the race, but they did not consult the proper authorities, an official inquiry found.
Another runner, Kate Sanderson, who lost part of her foot, settled with race organisers last year.
Ms Pitt, who had to wear a compression suit over her face, neck and body, lost four fingers and a thumb.
Her lawyer, Greg Walsh, said details of her settlement with race organisers were confidential. Other local reports said the payout was about A$10m ($9.3m, Â£5.5m).
"She's very relieved to put the case behind her," he said, adding that even after the surgery she had already received, she still needed further treatment for her injuries.
Ms Pitt would have faced several more years in court had she not settled, he added.
"It has been very stressful. She now looks forward to getting on with her life and starting a family with her partner Michael Hoskin," Mr Walsh added.
An ultramarathon runner who suffered severe burns after being trapped in a bushfire in Australia has received a multi-million dollar settlement.