The man had just turned 29 shortly before he was spotted, according to police records.
Officers responded around 1 a.m. Saturday to a report of a man riding a white horse on eastbound 91 Freeway in Long Beach from Paramount Boulevard to Downey Avenue. Officers found the man on his horse after he had exited at Downey and rode into Bellflower.
They stopped the man and administered field sobriety tests, with results of 0.21 and 0.19 percent -- or more than double the legal limit.
The man was arrested and identified as Luis Alfredo Perez, of Placentia.
Guera, his horse, was unharmed and released to the man's mother.
The California Highway Patrol offered a simple message to the public: "No, you may not ride your horse on the freeway, and certainly not while intoxicated," the agency wrote on Twitter.