The next season, in 2005–06, Carter made the Flyers' roster out of training camp.
He was joined by fellow rookies Mike Richards and R. J. Umberger, who were both also instrumental in the Phantoms' Calder Cup championship of the previous season.
He scored his first career NHL goal on October 27, 2005, against Roberto Luongo of the Florida Panthers.
He finished the campaign first in team-scoring among rookies with 23 goals and 42 points.

After 37- and 53-point efforts in his second and third NHL seasons, respectively, Carter and the Flyers agreed to a three-year, $15-million contract extension on June 27, 2008, days before he was set to become a restricted free agent.
He responded with a breakout campaign in 2008–09, leading the team in scoring with 46 goals and 84 points.
During the season, he was also named to his first NHL All-Star Game, representing the Eastern Conference.
Despite a strong regular season, Carter was held to just one goal in six Stanley Cup playoff games as the Flyers were eliminated by the Pittsburgh Penguins in six games.
 His series was also marred when he failed to score with an open net in front of him in Game 2 of the series, where Penguins goalie Marc-André Fleury made a toe save to block the shot that would have given the Flyers a 3–1 lead late in the third period.
Carter was later called off for a hooking penalty and the Penguins scored to tie the game and eventually win in overtime.
It was later revealed that Carter had played the final four games of the series with a separated shoulder.

On November 13, 2010, Carter signed an 11-year, $58 million contract extension with the Flyers through to the 2021–22 season.
The next season, in 2005–06, Carter made the Flyers' roster out of training camp. He was joined by fellow rookies Mike Richards and R. J. Umberger, who were both also instrumental in the Phantoms' Calder Cup championship of the previous season. He scored his first career NHL goal on October 27, 2005, against Roberto Luongo of the Florida Panthers. He finished the campaign first in team-scoring among rookies with 23 goals and 42 points.
After 37- and 53-point efforts in his second and third NHL seasons, respectively, Carter and the Flyers agreed to a three-year, $15-million contract extension on June 27, 2008, days before he was set to become a restricted free agent. He responded with a breakout campaign in 2008–09, leading the team in scoring with 46 goals and 84 points. During the season, he was also named to his first NHL All-Star Game, representing the Eastern Conference. Despite a strong regular season, Carter was held to just one goal in six Stanley Cup playoff games as the Flyers were eliminated by the Pittsburgh Penguins in six games.  His series was also marred when he failed to score with an open net in front of him in Game 2 of the series, where Penguins goalie Marc-André Fleury made a toe save to block the shot that would have given the Flyers a 3–1 lead late in the third period. Carter was later called off for a hooking penalty and the Penguins scored to tie the game and eventually win in overtime. It was later revealed that Carter had played the final four games of the series with a separated shoulder.
On November 13, 2010, Carter signed an 11-year, $58 million contract extension with the Flyers through to the 2021–22 season.
Jeff Carter