Jonathan Quick made 22 saves for his third shutout of the playoffs, and the Kings combined second-period goals by Alec Martinez and Anze Kopitar with third-period power-play goals by Jeff Carter and Justin Williams. They now take a three games to none lead in the best-of-seven series.
Game 4 will be played Wednesday at Staples Center.
Only once has a team taking a 3-0 lead in a final failed to win -- the 1942 Detroit Red Wings, who lost to the Toronto Maple Leafs.
After a scoreless first period, Martinez opened the scoring five minutes, 40 seconds in the second period, putting a rebound of a shot by Dwight King past New Jersey goaltender Martin Brodeur for his first career playoff goal in 23 games.
The Kings increased their lead to 2-0 at 15:07 of the second period as Kopitar scored his eighth goal of the playoffs, equaling the playoff high by Danny Briere and Claude Giroux, both of the Philadelphia Flyers.
Carter scored a power-play goal at 4:15 of the third period, 46 seconds after Devils defenseman Mark Fayne was called for cross-checking.
Williams scored at 6:47, 1:17 after New Jersey defenseman Marek Zidlicky's high-sticking penalty.
The Kings had failed to score on each of their first three power-play opportunities of the series, their 18 last, and scored on six of their previous 77 power-play opportunities in the playoffs, 7.8 percent.
Drew Doughty was credited with an assist on Williams' goal for his 13th point of the playoffs, the most among all NHL defensemen.
The Kings killed off all six Devils power-play opportunities, including a two-man disadvantage for 59 seconds of the first period.
New Jersey led 22-21 in shots on goal. Brodeur made 17 saves.
The crowd of 18,764 was the largest for a hockey game at Staples Center, which opened in 1999.
The Kings are the first team to take three games to none leads in each of their four playoff series since the NHL adopted the best-of-seven format for all four playoff rounds in 1987.
- Steven Herbert of City News Service