[2][3][4] She grew up idolising Melbourne captain Daisy Pearce and Western Bulldogs premiership player Bonnie Toogood,[2] as well as Australian Olympic gold medallist Cathy Freeman.

[5] McNamara played under-18s football for the Sandringham Dragons in the NAB League Girls,[2][3][4][6] averaging 17 disposals and six tackles in three matches before the season was shut down due to the COVID-19 pandemic.

[10][11][9] On her first day of pre-season, she won the club's two-kilometre time trial ahead of regular winner Karen Paxman, again running in under seven minutes.

[1] McNamara made her AFL Women's debut in Melbourne's 21-point win over Gold Coast at Metricon Stadium in round 1 of the 2021 season, and was named among the Demons' best players with 18 disposals.

[14][15] She received a nomination for the 2021 AFL Women's Rising Star award in round 7 after recording 16 disposals and five tackles in Melbourne's win over Adelaide.