Tugnutt played several seasons in the National Hockey League (NHL) with the Quebec Nordiques, Edmonton Oilers, Mighty Ducks of Anaheim, Montreal Canadiens, Ottawa Senators, Pittsburgh Penguins, Columbus Blue Jackets, and Dallas Stars.

While a member of the Nordiques on March 21, 1991, Tugnutt set a modern-day NHL record for most saves in a regular-season game when he stopped 70 of 73 shots in a 3–3 tie with the Boston Bruins.

After retiring as a player, Tugnutt served as the president, governor, and coach of the Central Canada Hockey League's Kemptville 73's.

He was primarily used as a backup during his first three pro seasons, bouncing up and down between the Halifax Citadels of the American Hockey League (AHL) and the parent club in Quebec City.

On March 21, 1991, Tugnutt stopped 70 of 73 shots to earn his team a 3–3 tie against the Boston Bruins, the highest number of saves made in a regular season game in NHL history.

[6] His performance evoked such respect that after it was over, several Bruins players skated over to congratulate Tugnutt[7] while the Boston fans gave him a standing ovation.

[citation needed] In 1995, Tugnutt signed a one-year deal with the Washington Capitals, and subsequently spent the entire 1995–96 season with their AHL affiliate, the Portland Pirates.

Goaltending coach Phil Myre helped Tugnutt work on fundamentals, and gained confidence and improved his game each season.

While in Ottawa, he went from fighting for the backup position with Mike Bales to splitting duties with starter Damian Rhodes the next two seasons, and became the team's undisputed starting goaltender by 1999.

However, he was unable to match his previous season and Ottawa traded him to the Pittsburgh Penguins for an experienced playoff goaltender, Tom Barrasso.

Both Ottawa and Pittsburgh attempted to re-sign Tugnutt but were unable to match the lucrative contract offered by the expansion Columbus Blue Jackets.

General Manager Doug MacLean gave Denis the opportunity to be the sole starter on the club, and traded Tugnutt to the Dallas Stars.

[20] Tugnutt previously owned the Kemptville 73's, a Junior "A" ice hockey team, where he served as head coach, president and governor.

After a disappointing 4-game sweep in the NHL playoffs, Tugnutt was more than excited to play for Team Canada in the 1999 World Hockey Championships.