Chandler Stephenson and Jonathan Marchessault also scored for Vegas while Robin Lehner, the number one goaltender following the departure of Marc-Andre Fleury to Chicago, made 25 saves.
Ryan Donato scored the first goal in the history of the Kraken franchise. Jared McCann and Morgan Geekie also scored while Phillip Grubauer made 18 saves as Seattle's rally from a 3-0 deficit came up just short.
Story of the game
As expected with an expansion team, Seattle came out nervous, but Jordan Eberle did hit the post 30 seconds into the game and the Kraken went on their first-ever power play when Alex Pietrangelo was whistled for tripping.
After Vegas killed off the penalty, which featured a breakaway by William Karlsson, they took the lead as Pacioretty snapped a wrist shot past Grubauer's right that went over his glove.
The Golden Knights would make it 2-0 after Karlsson created a turnover in the offensive zone and Marchessault eventually found the back of the net.
The hosts went on their first power play as Jamie Oleksiak tripped Reilly Smith and later on at the other end, Lehner stoned Brandon Tanev with a poke-check save.
Seattle outshot Vegas 9-6 in the first period, but trailed by two goals heading to the intermission.
The Kraken penalty kill was able to keep the Golden Knights power play off the board after a Jaden Schwartz holding penalty and a subsequent too many men on the ice call shortly after.
Nicolas Hague was allowed to drift into the slot and after his shot went through traffic, he appeared to have his first goal of the season, but Pacioretty was later credited with his second of the night as Vegas now held a 3-0 advantage.
The historic first goal for Seattle came seconds after Vegas killed a Zach Whitecloud holding penalty as Donato fired a rebound past Lehner to become the answer to a trivia question and make it 3-1.
It was quickly 3-2 as McCann was credited with the goal as it trickled over the goal line.
Marchessault hit the post as Vegas was now leading in the overall shot tally 24-23 and took a one-goal lead into the third period.
Stunningly, the Kraken had tied the game when Geekie's wrist shot eluded Lehner at the near post.
Stephenson would score the winner when he deflected a pass from Mark Stone into the net with his skate. The goal was reviewed for a kick, but the call stood.
Alec Martinez nearly made it 5-3 when he clattered his shot off the post, the third Golden Knight to find the iron.
Seattle tried to use their bit of good fortune to tie the game by pulling Grubauer with 1:20 left, but Lehner made a kick save and Stone cancelled out an inning as a valiant effort by the Kraken came up just short.