Gibson, with only three career regular-season NHL starts under his belt, got the call over veteran Jonas Hiller, who came in to relieve rookie Frederik Andersen midway through the third period of Game 3. Andersen remains out with a lower body injury.
Hiller started the first two games of the series, both losses at Honda Center.
Gibson, 20, went 3-0-0 with the Ducks this season, sporting a .954 save percentage after stopping 83 of 87 shots he faced. He was given the start late in the regular season in a huge game against San Jose, stopping 36 of 38 shots as the Ducks won to clinch the Pacific Division.
Gibson, a second-round pick by the Ducks in the 2011 draft (39th overall), also backstopped AHL Norfolk to a playoff series upset over the Kings' AHL team in Manchester in the opening round. He sported a .955 save percentage and a 1.45 goals-against average in six AHL playoff games this spring. He was recalled from the AHL on Friday.