Madera County sheriff's officials say the man was swimming near the Jackson Swimming Hole, just east of Tenaya Lodge, around 4 p.m. when he slipped and fell.
A group of 20 rescuers hiked a mile to find him and used a rope to pull him across a creek and back to safety.
The 31-year-old suffered major injuries in the fall. He was taken to Community Regional Medical Center in Fresno by helicopter.