Mannon McMahon is an American forward from Maple Grove, Minnesota, who developed through Maple Grove High School before joining the University of Minnesota Duluth. Over five collegiate seasons with the Bulldogs, she became known for her speed, work ethic and durability, never missing a game and establishing a UMD record with 173 consecutive games played. McMahon served as team captain during her final season and finished her college career with 31 goals and 56 assists for 87 points. She was also named UMD’s Most Outstanding Senior Female Athlete in 2023–24. 

McMahon was selected 26th overall by the Ottawa Charge in the fifth round of the 2024 PWHL Draft and earned a roster spot following training camp. She made an immediate impact, scoring the first goal of her PWHL career in Ottawa’s home opener against Toronto on December 3, 2024. She appeared in all 30 regular-season games as a rookie, recording four goals and four assists, before adding another goal in eight playoff games. Her postseason goal, a third-period winner against Montréal, made her the first Ottawa rookie to score in the PWHL playoffs. McMahon also earned an opportunity to represent the United States during the 2024–25 Rivalry Series. 

In January 2026, McMahon was acquired by the Vancouver Goldeneyes in a six-player trade, joining former UMD teammates Ashton Bell and Nina Jobst-Smith. She finished Vancouver’s inaugural season with three goals and one assist in 17 games, including three goals over a four-game stretch in March. In June 2026, the Goldeneyes re-signed McMahon to a two-year contract through the 2027–28 season. Her combination of speed, physical play, consistency and relentless work ethic has made her an important part of Vancouver’s developing roster as she continues her professional career.