He became known for his aggressive style of play and began to also show his penchant for offensive production as he improved to 18 goals and 38 points in his fourth season in 2002–03.

As NHL play resumed the next season, in 2005–06, Fisher emerged with 22 goals and 44 points, providing valuable secondary scoring for the Spezza-Heatley-Alfredsson line.

He helped the Senators to a first seed in the Eastern Conference going into the playoffs, but they were defeated by the fourth-seeded division rivals Buffalo Sabres in five games in the second round.

With a career-high plus-minus (+/-) rating of +23 in the regular season, Fisher was nominated for the Frank J. Selke Trophy as the best defensive forward.

He finished as second runner-up behind Jere Lehtinen of the Dallas Stars and trophy-winner Rod Brind'Amour, captain of the Stanley Cup champion Carolina Hurricanes.

He was kept to 68 games due to a left knee injury, sustained on December 27, 2006, against the New York Islanders,[5] forcing him to sit out four weeks.

In the playoffs, Fisher helped the Senators to the 2007 Stanley Cup Finals, where they fell short to the Anaheim Ducks in five games.

However, Fisher was forced to miss the playoffs, injuring his left knee in a knee-on-knee hit from Toronto Maple Leafs forward Mark Bell in the final game of the regular season.

[21] On January 31, 2018, Fisher announced that he intended to end his retirement to help the Predators make another Stanley Cup run.

[32] On July 10, 2010, Fisher married Underwood at The Ritz-Carlton Lodge, Reynolds Plantation, in Greensboro, Georgia, with more than 250 people in attendance.

[33][34] Underwood surprised Fisher by having one of their favorite artists, Brandon Heath, sing his song "Love Never Fails" for their first dance.