Gallagher is an athletics competitor, competing in long jump, discus, shot put, javelin and sprinting, She became involved in athletics after learning about the Paralympics. At the skills assessment, the classifiers had her try shot put and, despite being dressed in casual athletic attire, she managed a throw that met the Paralympic qualifying distance. After a year of training, she increased this initial distance by to have a personal best throw of over . She holds several records in the F13 classification, including Australian and Oceanian records in the long jump, javelin and shot put, and an Australian record in discus. In athletics, her coaches have included Mike Edwards and John Boas. In January 2011, she competed at the 2011 Christchurch IPC Athletics World Championships, where she finished second in the long jump and third in the javelin throw event, with a throw of . Her appearance at the championships marked her return to the sport after having taken a break to compete in skiing.