Less than a year ago, Mr Leha couldn’t run for more than two minutes.
He weighed almost 170kg.
Within six months he shed more than 40kg, and completed the 42km New York Marathon - one of the world’s toughest road races.
Mr Leha still remembers the moment he crossed the finish line - an emotional embrace with Indigenous Marathon Foundation director, Robert De Castella.
“Even now, it brings me close to tears,” he said.
“It’s just the best thing I could’ve ever done for myself.”
Before his success, Mr Leha was on a dangerous path.
After losing his brother three years ago, he struggled with depression, ate unhealthy food and abused alcohol.
“The best gift you can ever give somebody is the gift of health for life."
Mr Leha said training for the New York Marathon saved his life.
"I probably would have lost my life if I didn't start running,” he said.
“If I didn't join the Indigenous Marathon Project. It was a fast way to spiralling out of control.”
Making a difference
His journey didn’t stop when the marathon ended.
He knew he had to stay healthy and keep running, so he started the Sydney Deadly Runners group.
The group varies in size from about four to seven runners, who meet up twice a week at 6am to train.
Sherry-Ann Toomey joined the Deadly Runners for one session last year, but found it too hard.
Ms Toomey came back to the group in 2016 following a life-changing tragedy.
"Last year in December, Christmas Eve, we lost our mum and I think from that day I made a commitment to her that you know I was gonna make a change with my life," she said.
Now she’s on the way to running Sydney’s City to Surf in August.
While fellow runner and friend, Warren Roberts has his eyes on New York.
"I'm looking forward to running a marathon, and maybe next time you hear from me, I've already done that,” Mr Roberts said.
For Mr Leha, seeing his friends on the same journey he started a year ago keeps him motivated.
“The best gift you can ever give somebody is the gift of health for life. And simply by passing on the lessons I've learned, I feel so fulfilled in my life."