The victory pushed the Galaxy (12-9-4) to second place in the Western Conference and third best record in the entire MLS.
Donovan kicked in a high shot to the left of the net in just the third minute of the first half over Vancouver goalkeeper David Ousted for the 1-0 lead.
"It puts your team in a really good position, and even if they score a goal, you're back where you started. So it's a nice way to start a game," said Donovan.
A usually confident Whitecaps team struggled to find their offensive rhythm in the beginning, and missed out on an opportunity to tie the game in the 10th minute. Gershon Koffie's shot was off wide right off the goal, however in the 15th minute Vancouver's Kenny Miller blew an opportunity to score when the ball bounced off his arm.
Robbie Keane had an opportunity to increase the lead in the 25th minute when his shot just went over the cross bar. Keane later had another opportunity to score and took a shot that went wide right and out of play.
The Whitecaps (10-9-6) lost the second consecutive game, and didn't help themselves in the Western Conference. Camilo who has 14 goals that ties an MLS record, began the game off the bench due to a severe groin injury that he suffered last week.
In his second start as Galaxy goalkeeper Jaime Penedo picked up his second career shutout in an MLS game.
"It was a grind-out road victory, one that we haven't had all year, so it was good to get one,'' Galaxy coach Bruce Arena said.