LAPD sources said the man was booked at police headquarters in downtown L.A. His name was not released.
Late Saturday, authorities said a person of interest was being questioned in connection with the incident after turning himself in at a Santa Monica police station. Los Angeles Police Department Lt. Andy Neiman said the man told police he was "connected" to the incident.
The car involved in the crash was found abandoned.
Several videos have emerged showing the crash, which left one person dead and at least 11 others hurt, including one in critical condition.
Witnesses said they believed the driver was traveling about 60 mph — others cited slower speeds — when the crash occurred about 6 p.m. Saturday near the boardwalk's intersection with Dudley Avenue, just before the sun began to set on the tourist haven. Witnesses said "scores of people" were walking along the beach.
"The vehicle appeared to be moving purposefully down the boardwalk, according to witnesses," Humphrey said. He said firefighters responding to the scene thought the driver might have had some kind of medical emergency, but the vehicle did not stop.
"A car plowed through the boardwalk," said Daniel Regidor, 50, who was running nearby when the crash occurred.
"People screaming, running. I was half a mile from the scene, but you could see just this mass of people trying to get out of the way.... Just a lot of people screaming.... It was horrible.
"I saw somebody flying up in the air," Regidor said. "When I came upon the scene, there were a bunch of people on the ground, bloodied."
Daniel Jenkins, 19, was selling medical marijuana-related art and souvenirs on the pedestrian walkway and witnessed the incident.
Jenkins said he saw a blue Charger turn off a side street onto the pedestrian walkway going about 35 mph.
"He started basically losing control," Jenkins said.
He said he saw the vehicle hit a woman who sells turtles and a man who appeared to be homeless.
"All the turtles flew everywhere," as did mannequins outside of storefronts, Jenkins said..
He said the vehicle appeared to speed up after it hit the pedestrians and "zoomed all the way down" for several blocks.
The famed boardwalk is a cultural hub known for its eccentricities. Galleries, restaurants, tattoo shops, skateboard parks and the famous outdoor weight room known as Muscle Beach attract locals and tourists alike.
The crash spurred many, including nearby lifeguards, to race "to the aid of strangers," Los Angeles Fire Department spokesman Brian Humphrey said.