Sedin's second goal, with 10 minutes to go in the third period, gave the Canucks a 4-2 lead. Sedin eluded a pair of defenders, cruised down the slot and fired a wrist shot past Corey Crawford for the eventual game-winner.
Sedin also tallied in the second period and his twin brother Henrik added a pair of assists as the Canucks established a commanding lead heading back to Chicago for Sunday's Game 3.
Jannik Hansen and Alexander Edler scored and Roberto Luongo turned aside 23-of-26 shots for Vancouver.
The defending Stanley Cup champion Blackhawks didn't go down easily. Ben Smith's second goal of game with less than 8 minutes remaining cut Chicago's deficit to one goal, but Luongo shut the door down the stretch.
Viktor Stalberg scored and Crawford finished with 23 saves for the Blackhawks.