According to the Montgomery County Sheriff's Office, it happened around 5:30pm at the River Plantation golf course in Conroe.
Officials said 36-year-old Jamie Teran was with his son on a golf cart. When they went to cross a bridge, one of the tires slipped off the track used for carts. Teran overcorrected and they crashed through the guardrail.
The golf cart fell 30 feet and landed upside-down on the rocks in a creek below, trapping them.
The boy was able to crawl to safety, but Teran's leg was severely injured.
A River Plantation Fire Department crew responded and rescued Teran. He was airlifted to Memorial Hermann Hospital in critical condition.
Teran's son was taken to an area hospital with minor injuries.