Marchand scored a short-handed goal to open the game's scoring but it was his quick shot 8:53 into the third period that broke a 2-2 tie and boosted the Bruins to the win.
Marchand converted a pass from Patrice Bergeron with the Bruins down a man 12 minutes into the game for the first goal of the day. About 6 minutes later, Torey King sent a slap shot past Los Angeles goaltender Jonathan Quick to covert a power play and the Kings were up 2-0.
The Kings got on the board with Willie Mitchell's first goal of the season early in the second period and tied the score when Jeff Carter beat the Bruins' goalie Chad Johnson while Los Angeles was on the power play.
Just 18 seconds later, Bergeron passed to Reilly Smith, who quickly fed Marchand to the left of the goal. Marchand fired the puck past Quick for what proved to be the final goal.
It was the fourth consecutive game in which Marchand scored at least one goal.
Johnson finished with 21 saves and Quick had 20.