[4] Hart was born in Sydney, Australia[3] and attended Sophia Mundi Steiner School in Abbotsford, Victoria until she was noticed at the age of 15 at a local shopping centre.

[9] Hart moved to New York City to pursue a career in modeling and has appeared in campaigns for Guess, Triumph, and Esprit.

[12][13] With Heidi Klum, Karolina Kurkova and Adriana Lima all pregnant in the fall of 2009, Hart appeared extensively in the season's Victoria's Secret catalogs.

[15] Hart was also in a few episodes of MTV's The City during its first season, in which she is shown dating Tamarama band member Nicolas Potts, her long-term boyfriend.

[16] She has participated in Tamarama music videos, such as "Everything To Me" (alongside fellow Australian model Miranda Kerr) and "Middle of a Magazine".

[17] In 2010, Hart walked in the Spring/Summer 2011 shows for Gottex Swimwear, PPQ, Louise Gray, Emilio de la Moreno, Osman, Sass & bide, Julien MacDonald, Matthew Williamson, Antonio Berardi, Christopher Kane, David Koma, Giles Deacon, Charlie Le Mindu and Jon.

[25] Hart and her then-boyfriend, Tamarama band member and fellow Australian Nicolas Potts, purchased a $1-million one-bedroom property in Manhattan's Battery Park during the summer of 2008.