Martone joined the Philadelphia Flyers when he signed a three-year, entry-level contract March 29, 2026, after leading Michigan State with 25 goals and 50 points in 35 games as a freshman. He had 30 points (14 goals, 16 assists) in his final 19 games, including a hat trick against Notre Dame on Feb. 20, finished his first college season with nine points (five goals, four assists) in a six-game point streak. He was the only freshman named to the All-Big Ten First Team, was named to the Big Ten All-Freshman team and led the 2026 IIHF World Junior Championship with six goals in seven games while totaling nine points for Canada as its captain.

Martone scored his first NHL goal to give the Flyers a 2-1 overtime victory against the Boston Bruins at Xfinity Mobile Arena in Philadelphia on April 5, becoming the first player in Flyers history to score his first NHL goal in OT. At 19 years, 161 days old, Martone was the second-youngest player in NHL history to have his first NHL goal come in overtime. Alexis Lafreniere was 19 years, 109 days old when he scored for the New York Rangers on Jan. 28, 2021. Martone is also the fourth teenager to score his first NHL goal in OT, along with Luke Hughes (19 years, 216 days on April 13, 2023) and Cody Ceci (19 years, 360 days on Dec. 16, 2013).

His first Stanley Cup Playoff goal helped the Flyers to a 3-2 win against the Pittsburgh Penguins in Game 1 of the 2026 Eastern Conference First Round. At 19 years, 174 days, he became the youngest player in team history to score in his postseason debut, besting the previous record set by Simon Gagne (20 years, 44 days) during Game 1 of 2000 Eastern Conference Quarterfinals.

Martone set three goals for himself as a high-end prospect entering his draft-eligible season: Become a dominant force with Brampton of the Ontario Hockey League, be a hard player to play against and one of the top players in scoring.

He was tied for seventh in the OHL with a Brampton-record 98 points (37 goals, 61 assists), including 29 power-play points (seven goals, 22 assists), in 57 games. He had nine points (four goals, five assists) and three power-play goals in the playoffs and was selected by the Flyers with the No. 6 pick in the 2025 NHL Draft.

Martone grew up in Peterborough, Ontario, in a hockey-playing family. His father, Mike Martone, played four seasons (1994-98) for Peterborough (OHL) and was captain in 1997-98. The family patriarch had Porter and his younger sister, Audrey, in skates by the time each was 2 years old.

Porter was chosen by Sarnia with the No. 5 pick in the 2022 OHL draft and was traded to Mississauga (now Brampton) on Jan. 7, 2023. He won a gold medal with Canada at the 2024 IIHF World Under-18 Championship, where he had 17 points (five goals, 12 assists) in seven games. His 23 points (eight goals, 15 assists) in 14 games at the 2023 and 2024 U18 Worlds set the career scoring record by a Canada player, surpassing Connor Bedard's 21.

He also won gold at the 2023 Hlinka Gretzky Cup and played at the 2025 World Junior Championship. He averaged 9:23 of ice time in two games at the 2025 WJC after initially being brought to the tournament as an extra player.