Los Angeles ended a six-game losing streak, the last three of those losses coming to walkoff home runs by the Texas Rangers.
The Angels raced to a 7-0 lead through three innings and turned things over to starter Garrett Richards (3-4), who gave up two runs on four hits in seven innings while throwing only 90 pitches.
Toronto starter Josh Johnson (1-8) faced additional struggles against the Angels, having come into the game with a 6.08 earned run average.
Los Angeles batted around in the first inning against Johnson with Howie Kendrick driving in a run with a single, Trumbo delivering his 24th homer and J.B. Shuck adding a run-scoring base hit.
Shuck, who hit the first home run of his 117-game career last Monday, also had a sacrifice fly in both the third and seventh innings.
Johnson eventually allowed six runs on 10 hits in just 2 1/3 innings.
Toronto had won its previous two games and fell to 2-2 on its 10-game western road trip.