She started her career as an academy player at Sheffield United, before joining Doncaster Rovers Belles in 2014, rejoining Sheffield United in 2018, and signing with Leicester City in 2020.[1][2][3] Her goal against London City Lionesses in April 2021 helped confirm Leicester's promotion to the Women's Super League ahead of the 2021–22 season.[4][5] Considered a core member of Leicester's squad, Tierney signed a new contract in 2023, committing to the club for a further two years.[6][7] She re-signed with Leicester again in 2025.[8]
International career
Tierney has represented England at youth level, playing for several age group teams from under-15 through under-21 level.[6]
Personal life
In 2021, Tierney graduated with distinction from Sheffield Hallam University with a master's degree in Sport Business Management, after previously completing an undergraduate degree in Sports Development with Coaching at the university.[9] She also attended a course to obtain her UEFA A coaching licence as part of an initiative to increase the number of female football coaches.[10]