The 51-year-old DeBoer was fired a day after the Sharks' 3-1 loss at Nashville.
The move comes amid a five-game losing streak and overall current record of 15-16-2, which puts them in 6th place in the Pacific Division.
DeBoer was 198-129-4 in parts of five seasons with San Jose.
He led them to the playoffs in all four of his past seasons, including a Stanley Cup Final in 2016. The series went six games before the Sharks ultimately fell to the Pittsburg Penguins.
He also has coached New Jersey and Florida
DeBoer is the fifth NHL coach to lose his job this season and the third for performance reasons.
New Jersey canned John Hynes and Toronto fired Mike Babcock after rough starts, while Calgary accepted Bill Peters' resignation following allegations of abuse in previous organizations and Dallas dismissed Jim Montgomery on Tuesday citing unprofessional conduct.''
The Sharks host the New York Rangers on Thursday night.
WHOA! Major #BreakingNews from out of San Jose. Pete DeBoer has been fired from his position of Head Coach of the @SanJoseSharks. The #SJSharks are 15-16-2 and sitting in 6th place in the Pacific. pic.twitter.com/O4Rl56c6XC— Dustin Dorsey (@DustinABC7) December 12, 2019
More — Early reports say the move is “purely a hockey decision”. DeBoer led the #SJSharks to the Stanley Cup in his first season at the helm. The team has not made it back since. pic.twitter.com/3WU30ntVEC— Dustin Dorsey (@DustinABC7) December 12, 2019
For those #SJSharks asking, what’s next? Look no further than to St. Louis. Fans sometimes think change will do nothing, the Blues were in last place, they fired their head coach and went to a Stanley Cup. How did that season end last year? Change is NECESSARY. pic.twitter.com/qdKZy89KZV— Dustin Dorsey (@DustinABC7) December 12, 2019