The No. 6 overall pick took over the starting role after veteran Tyrod Taylor suffered a chest injury before pregame warmups. Taylor, who started for the Chargers in Week 1, began Week 2 sidelined and was later ruled out of the game.
Herbert scored a four-yard touchdown run to close an eight-play, 79-yard drive in his first NFL start.
He completed 5 of 10 pass attempts in the first quarter.
Head coach Anthony Lynn named Taylor the starter at the beginning of training camp. The veteran led Los Angeles to a 16-13 season-opening victory over the Cincinnati Bengals last week, completing 16 of 30 pass attempts for 208 yards.