And in 2017, the father of two won the Mongol Derby, covering 1000km over 10 days – the longest horse race in the world.
“I have learnt so much about how to find comfort in the discomfort,” Fernon said on Thursday when his selection for Tokyo was ratified.
“I have been able to put myself into these difficult pressure environments and realised nothing can happen to me which I can’t handle.
“It gives me a huge amount of confidence to know I can walk into that Olympic space again, when all the pressure is on, and know that I can get through it and compete well.”
Fernon announced his return to modern pentathlon three months before the Oceania qualifiers last November in China.
The 31-year-old was the first Oceania athlete to finish the China event, securing Olympic selection.
“It’s a surreal experience to be back,” he said.
“The Olympics is what drives me on all those difficult training days when you’re sore and you’re tired, you don’t want to get out of bed.
“I have come back as a much more mature athlete … I’m much more aware this time that the Olympics is about so much more than just my performance. It’s such an opportunity to inspire other people.”
Australia’s reigning Olympic champion in the women’s modern pentathlon, Chloe Esposito, and compatriot Marina Carrier will soon accelerate their campaigns to earn Tokyo spots.
The pair can gain selection by securing one of six places based on the Olympic ranking list as at June 1 this year, or by finishing in the top three of non- qualified athletes at May’s world championships.