Harding began performing in the late 2000s through holiday drama courses, then moved on to television roles with an appearance in My Place and a three-episode run in season 3 of Packed to the Rafters. Her first major television role was as Sue Knight in Puberty Blues, one of the two teenage girls who were the main characters of the 1979 novel of the same name. Harding's role in the series led to her receiving the 2013 Logie Award for Most Popular New Female Talent, as well as being nominated for the 2013 Logie Award for Most Outstanding Newcomer, and nominated for the AACTA Award for Best Young Actor at the 2nd AACTA Awards in 2013. In 2017, she appeared in "Arkangel", an episode of the anthology series Black Mirror.