Known for her gritty, stay-at-home style of play as a shutdown defender, she was the first player to serve as team captain in Riveters history, a role she would hold for three years until her initial retirement.

[5] Johnston joined the New York Riveters for the Premier Hockey Federation's (PHF) inaugural season in 2015–16 as a defenseman.

[15][16] The Riveters won the Isobel Cup that season, with Johnston earning her first career playoff point with an assist.

[17] She made a comeback to return to the team for the 2019–20 season, earning three points in ten games.

[18] She had previously spent time as an assistant coach with the club while injured during the 2017–18 season.