Los Angeles County sheriff's officials said the incident happened around 2:30 p.m. in the Angeles National Forest, but they weren't alerted until 4 p.m.
A rescue helicopter was used to rescue the victim, whom authorities said is a man in his 20s. They said he fell about 200 feet into the canyon below.
He was taken to a local hospital with non-life-threatening injuries. He is expected to survive.
Authorities said the bridge is privately owned and the man trespassed to use a rope swing.
It was unclear how he fell.