Extreme athlete Dean Potter, renowned for his bold climbs and BASE jumps, was one of two men killed while attempting a wingsuit flight in Yosemite National Park.
Someone called for help late on Saturday after losing contact with Potter, 43, and his climbing partner, Graham Hunt, 29.
They had jumped from a 7,500-foot promontory called Taft Point, park ranger Scott Gediman said.
He said a search-and-rescue team looked for the men overnight but could not find them. Yesterday morning, a helicopter crew spotted their bodies in Yosemite Valley.
No parachutes had been deployed.
BASE jumping is an acronym for fixed objects in which someone can parachute from: building, antenna, span, and Earth (such as a cliff).
The sport is illegal in all national parks, and it was possible the men jumped at dusk or at night to avoid being caught by park rangers.
Potter and Hunt, who lived near Yosemite, were prominent figures in the park's climbing community, Mr Gediman said.
"This is a horrible incident, and our deepest sympathies go out to their friends and family," he said. "This is a huge loss for all of us."
Potter was famous for pushing the boundaries of climbing by going up some of the world's most daunting big walls and cliffs alone, using his bare hands and without ropes.
He took the sport to an extreme level with highlining - walking across a rope suspended between towering rock formations while wearing a parachute for safety in the event of a fall.
He drew criticism in May 2006 after he made a "free solo" climb of Utah's Delicate Arch in Arches National Park.
Though the climb was not illegal, outdoor clothing company Patagonia dropped its sponsorship of him, saying his actions "compromised access to wild places and generated an inordinate amount of negativity in the climbing community and beyond".
Potter defended his ascent, saying his intention was to inspire people to "get out of their cars and experience the wild with all their senses".
Last year, Clif Bar withdrew its sponsorship of Potter and four other climbers, saying they took risks that made the company too uncomfortable to continue financial support.
In more recent years, he combined his love of climbing and flying with BASE jumping. He also produced a film that chronicled his adventures BASE jumping with his dog, Whisper.
In 2009, he set a record for completing the longest BASE jump from the Eiger North Face in Switzerland by staying in flight in a wingsuit for 2 minutes and 50 seconds. The feat earned him the Adventurer of the Year title from National Geographic magazine.
A photographer who documented that jump, and knew Potter for more than 15 years said Potter stood out from other climbers not only for his skills but his boldness.
"In the adventure world, I've lost a lot of friends to climbing and BASE jumping," Corey Rich said.
"On one level, you lose a friend. But it's also difficult to be surprised because BASE jumping is the most dangerous thing you can do. The odds are not in your favour, and sadly Dean pulled the unlucky card."
Potter indicated in his writings that he knew the inherent danger of his sport.
"Though sometimes I have felt like I'm above it all and away from any harm, I want people to realise how powerful climbing, extreme sports or any other death-consequence pursuits are," he wrote in October.
"There is nothing fake about it whether you see it in real life, on YouTube or in a glamorous commercial."
The men wore wingsuits - skin-tight suits with batwing sleeves and a flap between their legs - to help them glide.
Last year Potter's friend and climbing partner Sean "Stanley" Leary died during a BASE jump in a wingsuit in Zion National Park in Utah.
Potter was among a group of people who recovered Leary's body.
Mr Gediman estimates that about five BASE jumping deaths have occurred in Yosemite. He said he himself watched a BASE jumper leap to her death in 1999 when her borrowed chute failed to open.
The woman was participating in a protest against the National Park Service's ban on BASE jumping.