Cesar Diaz was a rising star with Golden Boy Promotions.
Investigators say he was driving a 2016 Honda Accord with a female passenger when he lost control, drifted into the opposite lane and onto the dirt shoulder, then crashed into a tree. The car rolled onto the passenger side, ejecting Diaz.
He was pronounced dead at the scene and the female passenger was transported to a local hospital with multiple fractures.
"Everyone at Golden Boy Promotions is heartbroken over the passing of Cesar Diaz over Thanksgiving weekend," the boxing promotion company headed by Oscar de la Hoya said in a statement on Facebook.
"As talented and aggressive as he was in the ring, anyone who met Cesar knew how kind and nice he was outside of it. Our thoughts and prayers are with Cesar's girlfriend who remains in critical condition and his entire family."
Officials are still investigating the cause of the accident and asked anyone with information to call the Palmdale Station's Traffic Department at (661)272-2400.