Her mother, her aunt, Maxine Blomquist, her sister, Kate Heffernan and a cousin, Shirley Langrope, are all New Zealand netball internationals.

[2][3][4][5] The Heffernan family live on their sheep and beef farm, near Tapanui, West Otago.

[6] The Heffernan sisters attended Tapanui's Blue Mountain College[7] and St Hilda's Collegiate School.

In the 2016 final, Georgia scored 25 from 35 as St Hilda's defeated Marlborough Girls' College 38–37.

[14][15][16][17][18][19] Ahead of the 2018 season, while playing for Netball South, they were also named as training partners for Southern Steel.

[23][24][25] On 28 June 2020, during a Round 3 match against Northern Stars she suffered an ACL injury after landing awkwardly.

During the series she played against the senior New Zealand team, featuring her sister Kate Heffernan.

[3][23][39][40] On 20 January 2024, Heffernan made her senior debut for New Zealand against Australia during the 2024 Netball Nations Cup.

[1][7] Georgia and Kate Heffernan also won national titles representing St Hilda's Collegiate School.