He served as the head coach of the Florida Panthers from 2008 to 2011, the New Jersey Devils from 2011 to 2014, the San Jose Sharks from 2015 to 2019, and the Vegas Golden Knights from 2020 to 2022.
The Whalers advanced all the way to the J. Ross Robertson Cup Finals before losing to the Barrie Colts 4–2 in the seventh and series deciding game.
After the season, both DeBoer and his assistant, Steve Spott, decided to leave the Whalers and join the Kitchener Rangers in similar positions.
Marie Greyhounds in the first round, followed by a five-game series win over the Guelph Storm, setting up a Western Conference matchup against DeBoer's former team, the Plymouth Whalers.
DeBoer led the Rangers to a perfect 3–0 record during the round-robin portion of the tournament, sending Kitchener to the finals against the Hull Olympiques.
DeBoer led the Rangers to a first round victory over the Erie Otters, then helped Kitchener to a stunning series sweep over the powerful Owen Sound Attack.
They then increased their point total to 98 in the following season, 2006–07, finishing third in the Western Conference and easily sweeping the Sarnia Sting in the first round.
With the Rangers being named the host of the 2008 Memorial Cup, Kitchener put together one of the best regular season's in OHL history, finishing with a 53–11–4 record, earning a League-high 110 points to win the Hamilton Spectator Trophy.
The DeBoer-led Rangers quickly swept the Plymouth Whalers and Sarnia Sting in the first two rounds before disposing the Sault Ste.
Kitchener exploded for a 9–0 win and would face the Western Hockey League (WHL)'s Spokane Chiefs in the final game.
On June 13, 2008, the Florida Panthers in the National Hockey League (NHL) hired DeBoer as the team's head coach.
On December 26, 2014, after leading New Jersey to a subpar 12–17–7 record, the Devils fired DeBoer, replacing him with both Scott Stevens and Adam Oates in a dual-coaching setup.
[4][5] On January 15, 2020, DeBoer was hired as the head coach of the Vegas Golden Knights, replacing Gerard Gallant.
[8] The Golden Knights finished the 2021–22 season with a 43–31–8 record under DeBoer's leadership and failed to make the playoffs for the first time in franchise history.
[9] On June 21, 2022, just over one month after his dismissal from Vegas, DeBoer was hired as the head coach of the Dallas Stars, replacing Rick Bowness.