The man suffered no injuries, the Orange County Fire Authority reported.
Firefighters and paramedics were dispatched about 9:40 a.m. Thursday to the area of Trabuco Creek and Rosenbaum roads regarding a person in a creek.
Crews found a vehicle up against trees in a creek filled with rushing water and a man hanging onto an adjacent tree. It was unclear how he got there.
A rescuer was lowered from a helicopter, and the man was safely extracted from the creek.
"We strongly encourage everyone to stay clear of all moving water," according to an Orange County Fire Authority news statement. "It does not take a lot of water to move a person or a vehicle down river."
OC firefighters rescue man hanging onto tree at swift-moving San Juan Capistrano Creek amid storm