Alex Martinez's point shot was good for the winner at 5:47 of overtime, a shot that got past several bodies and appeared to hit a Chicago stick before beating goalie Corey Crawford.
The Kings will now face the New York Rangers in the Stanley Cup final. Game 1 begins in Los Angeles on Wednesday, with Hockey Night in Canada coverage on CBC-TV and CBCSports.ca at 7:30 p.m. ET.
The Kings have now passed three straight seven-game tests en route to the final series.
Los Angeles can win the championship for the second time in three seasons, while New York is looking for their first Cup win since the 1994 championship season.
The Kings and Rangers have met just twice in the playoffs, and not since 1981.
Chicago was looking to become the first team in 16 years to win consecutive Stanley Cups.
More to come