The win moves the Raiders (5-4) into first place in the AFC West, while division rival San Diego (4-5) suffered their fourth successive defeat.
Palmer, playing in his third game with Oakland, completed 14 of 20 pass attempts for 299 yards and two touchdowns to rookie receiver Denarius Moore.
"Our offense is going to be scary," Raiders linebacker Kamerion Wimbley told reporters. "Carson has only been here three games, but we trust in him.
"He's extremely intelligent, experienced, has a great arm and is becoming one of our leaders. It's just going to get better and better from here."
Raiders running back Michael Bush rushed for a season-high 157 yards including a two-yard touchdown, and added another 85 yards on three catches.
"I came in at halftime and coach said he was going to give it to me 15 more times," Bush said after gaining 86 yards in the first half. "I told him, 'Just feed the stud!' So he did."
The Raiders led 17-3 at halftime, but the Chargers, dismal before the break, scored on their opening drive of the second half on a 30-yard pass from Philip Rivers to Vincent Brown to energize the home crowd.
"We make games a little harder than they should be sometimes," Raiders coach Hue Jackson said. "It's not easy, but we'll keep working at it. This is a resilient bunch. We hadn't played well for the last two weeks, and it was time for the Raiders to stand up."
On the ensuing Raiders drive, Palmer connected with Bush on a 55-yard screen pass on a pivotal third down, and two plays later threw a 26-yard scoring pass to Moore to restore the two-touchdown lead.
"Ultimately you have to stand on your own in all three phases, but we have to help each other. We can play better than that on offense and defense, but we didn't in the first half."
Jacob Hester scored for the Chargers on a seven-yard pass from Rivers as the third quarter expired.
(Reporting by Mike Mouat in Windsor, Ontario; Editing by Alastair Himmer)