Gillis took over as general manager from the fired Dave Nonis after the 2007-08 season. The Canucks advanced to the 2011 Stanley Cup Finals under Gillis before losing to Boston, and since then the team has been in a steady decline.
"The Vancouver Canucks had success under Mike's leadership, and we nearly reached our ultimate goal; but I believe we have reached a point where a change in leadership and new voice is needed," team owner Francesco Aquilini said in a release.
The Canucks lost in the first round of the playoffs for two straight seasons before missing the postseason entirely for the first time since 2008.
Vancouver fans appeared fed up with the team's downturn and chanted for Gillis to be fired as the Canucks lost 3-0 to the Anaheim Ducks on Monday night.
Gillis signed a contract extension after the 2011-12 season. There were indications last week he and first-year head coach John Tortorella weren't communicating. Gillis seemed to criticize Tortorella's style in a radio interview, saying he wanted the team to get back to the type of game that got it to the 2011 Cup finals.
"I want us to play upbeat, puck possession, move the puck quickly, force teams into mistakes, high-transition game," Gillis said in an interview with the Team 1040. "I think we have the personnel to do it. If we don't have the personnel to do it, they'll be changed.
"That's my vision, that's how I believe you are going to win in the Western Conference and the National Hockey League. If you look at the top teams in the West, there isn't a lot that separates any of the teams in the West, but the top teams play that way. That's the way we played."
Tortorella has preached a defense-first, puck-pressure, shot-blocking style since taking charge of the club in the offseason after Alain Vigneault was fired following the 2013 first-round playoff exit. That has been Tortorella's coaching style in previous stints with the Tampa Bay Lightning and New York Rangers.
Apart from this season's product on the ice, Gillis had also been roundly criticized for his poor draft record, questionable free-agent signings and trades, and the handling of the Roberto Luongo saga.
After the veteran goalie was unseated in the Vancouver crease by Cory Schneider, Gillis tried to move Luongo and his massive contract -- one that Gillis himself had negotiated. When Luongo couldn't be dealt, Schneider was sent to the New Jersey Devils at last summer's draft.
In another surprising twist, Luongo was then traded back to the Florida Panthers last month following Tortorella's decision to start backup Eddie Lack in the Heritage Classic game.
In just over eight months, a position that had been the Canucks' strength became a major question mark.
Canucks Fire GM After Missing Playoffs
Pierre LeBrun discusses what has gone wrong for the Vancouver Canucks that led to the firing of GM Mike Gillis.