The self-described "professional adventurer" died Feb. 8 of an apparent heart attack in Henderson, his wife, Tiffany, said Sunday.
Fairfax gained international attention in 1969 when he became the first person in recorded history to cross the Atlantic alone by rowboat. He dealt with sharks, storms and exhaustion on the six-month, 5,000-mile journey from the Canary Islands to Florida.
In 1972, he and his girlfriend, Sylvia Cook, became the first known people to row across the Pacific Ocean. He survived a shark attack and cyclone on the yearlong, 8,000-mile trek from San Francisco to Australia.
Fairfax wrote separate books about his ocean crossings that were both published in the 1970s.
"He was a man of unbelievable strength and courage and confidence in everything he did," Tiffany Fairfax told The Associated Press. "He thought nature was a worthy challenge, and he loved nature."
John Fairfax used two different custom-made boats on the ocean journeys, she said, and used the stars to help him navigate. He survived by eating up to eight pounds of fish a day. He had a system to convert ocean water into drinking water.
"On the Pacific, a shark took a big chunk of his arm out" when he was spearing fish, Tiffany Fairfax said. "There you are on the Pacific Ocean and there's no hospital, and you need to row. He was an amazing, amazing human being."
John Fairfax enjoyed many other adventures, including a trip to the Amazon jungle and a stint as a pirate. He also spoke five languages, was a talented chef and regularly played the card game baccarat at Las Vegas casinos, his wife said.
"He believed a human could accomplish anything if they had confidence," she said. "When he would get an idea in mind, he would pursue it and say, 'I can do it.'"
Cook, 73, who lives near London, remained lifelong friends with John Fairfax.
"He's always been a gambler," Cook told The New York Times after his death. "He was going to the casino every night when I met him — it was craps in those days. And at the end of the day, adventures are a kind of gamble, aren't they?"
His only immediate survivor is his wife of 31 years, who moved with him to Las Vegas in 1992 after a hurricane in Florida where they had lived. No public services were planned.