Carl Gunderstrom had a goal and an assist, and Trevor Lewis had two assists for the Kings. Cam Talbot made 15 saves.
Brett Leason scored his third goal of the preseason, and John Gibson made 36 saves for the Ducks.
Kevin Fiala scored on a wraparound at 4:09 of the first period to give the Kings a 1-0 lead.
Kempe made it 2-0 with a power-play goal at 11:10, and Grundstrom scored 25 seconds later to push it to 3-0.
Leason cut it to 3-1 at 9:50 of the second period. His initial shot was saved by Talbot, but the rebound deflected in off the skate of Kings defenseman Mikey Anderson.
Blake Lizotte swatted in a rebound in the crease at 8:29 of the third period for the 4-1 final.
