Frederic signed an eight-year, $30.8 million contract (average annual value of $3.85 million) with the Edmonton Oilers on June 27, 2025. He was traded to Edmonton by the Boston Bruins on March 4 of that season and had four points (one goal, three assists) to help the Oilers reach the Stanley Cup Final, a six-game loss to the Florida Panthers.

Frederic decided to remain with the Oilers in lieu of becoming an unrestricted free agent. He was selected by the Bruins in the first round (No. 29) of the 2016 NHL Draft and signed his entry-level contract with Boston on March 13, 2018. He signed a two-year, $4.6 million contract Aug. 1, 2023, to avoid a salary arbitration hearing.

Frederic was an alternate captain at the University of Wisconsin as a sophomore in 2017-18, when he led the Badgers with 17 goals. He was named the 2017 Big Ten Freshman of the Year with 33 points (15 goals, 18 assists) in 30 games, becoming the first Wisconsin player to earn the honor since Dany Heatley in 1999-00. Frederic ranked fourth among all college freshmen in points per game (1.18) and was second in the NCAA with five short-handed points.

Frederic represented the United States on several occasions. He won bronze at the 2018 IIHF World Junior Championship, where his five goals in seven games were second on the team. He also played seven games at the 2016 Under-18 World Junior Championship (four goals, three assists).

Prior to attending Wisconsin, Frederic played two seasons (2014-16) for the United States National Team Development Program.