Pistorius began her professional acting career at the age of 19, when she made her television debut in the American television series Legend of the Seeker in the episode "Confession”, playing Luna.[5][6] Pistorius played the role of Chloe in the romantic drama film The Most Fun You Can Have Dying, directed by Kirstin Marcon, which was released on 26 April 2012.[7][8] The same year, Pistorius appeared as Amy in the comedy series Hounds.[9][10]
In 2013, Pistorius appeared as Rose Harper in the crime drama series The Blue Rose. The same year, she was cast in the miniseries Paper Giants: Magazine Wars, playing Beth Ridgeway, as well as the comedy-drama series Offspring, where she played the supporting role of Eloise Ward.[11]
In 2015, Pistorius co-starred with Kodi Smit-McPhee, Michael Fassbender and Ben Mendelsohn in the Revisionist Western film Slow West, where she played the role of Rose Ross. It premiered at the 2015 Sundance Film Festival on 24 January 2015 and was first released on 15 May 2015 in the United States, with a simultaneous release on video on demand.[12][13]
In 2016, Pistorius was cast in the romantic drama film The Light Between Oceans, in which she played the character Lucy Grace Rutherford / Adult Lucy Grace.[14][15] The same year, Pistorius played the role of Laura Tyler in the biographical film Denial.
Pistorius then played Lorraine Cassidy in the 2017 Australian post-apocalyptic horror drama film Cargo. The same year, she was cast in the miniseries Wake in Fright, as Janette Hynes.[16]
In 2018, Pistorius was cast to play the role of Anne in the comedy-drama film Gloria Bell, also starring Julianne Moore.[17] The same year, she appeared in the post-apocalyptic steampunk film Mortal Engines.[18][19]