She won a silver medal for Great Britain with Katherine Grainger in the women's double sculls at the 2016 Summer Olympics.

After completing her secondary education at Bishop Heber High School, she went on to study Business Management at the University of Bath and graduate from the GB Rowing Team Start programme.

[4] Before rowing, Thornley was a national championship winning show jumper, having participated since the age of twelve.

[8] She was part of the British squad that topped the medal table at the 2011 World Rowing Championships in Bled, where she won a bronze medal as part of the eight with Alison Knowles, Jo Cook, Jessica Eddie, Louisa Reeve, Natasha Page, Lindsey Maguire, Katie Greves and Caroline O'Connor.

[11] In June 2017 Thornley won the gold medal for women's single sculls in the European Rowing Championship at Račice.