Nick Perbix had three assists, and Andrei Vasilevskiy made 26 saves for the Lightning (32-15-1), who have won three in a row, all at home, and played their final game before the NHL All-Star break.
Tampa Bay defeated the Minnesota Wild 4-2 on Tuesday and the Boston Bruins 3-2 on Thursday.
"It was three tough teams to play in this league -- big, strong, fast playoff teams, and our guys handled it well," Lightning coach Jon Cooper said. "If there was a little bit of worry it was after a big win against the Bruins, and our impending break, how would we handle this game and would we look past it. They didn't and they got the points we needed."
Jaret Anderson-Dolan and Phillip Danault scored for the Kings (28-18-6), who had won their previous three, including a 4-3 victory against the Florida Panthers on Friday. Jonathan Quick made 20 saves.
"We made three or four mistakes [in the first period] and they ended up in our net," Los Angeles coach Todd McLellan said. "That happens often in a game, it's just that these guys capitalized on it."
Brayden Point gave Tampa Bay a 1-0 lead at 5:02 of the first period when he scored in front after Nikita Kucherov fed him from behind the net.
Pierre-Edouard Bellemare made it 2-0 at 6:21 from the high slot after Perbix picked off a pass near the right boards.
"At times it's a challenge for [the fourth line] to try to create some offense," Bellemare said. "But it's not just about the goals. To be able to play at the end of the game and have the coaches trust us to do the right thing, that's something you want to be able to bring. Sometimes you get rewarded for doing the right things."