She was a member of the Australian national team from 2006–2018, replacing the likes of Eloise Southby-Halbish, Megan Dehn, and Cynna Kydd.

[1] From 2003 to 2005 Pettitt was the cornerstone of Australia's development squads, with her notable leadership, composure, and shooting accuracy and reliable volume.

She moved to Sydney in early 2006 and made her debut for Australia at the Melbourne 2006 Commonwealth Games at which she was a recipient of a silver medal.

Pettitt was identified in her early teens by selectors and rose through the junior representative ranks with speed and poise including AIS and NSWIS scholarships.

[5] Pettitt took the court for the Sydney Swifts during their premiership-winning Commonwealth Bank Trophy season,[6] forming a partnership with fellow Australian representative Catherine Cox.

Pettitt put her name in the history books after executing a perfect shooting performance during the Commonwealth Bank Trophy Grand Final match and shot 26 goals without a miss.

In the Grand Final at Acer Arena on 28 July 2008 the New South Wales Swifts defeated the Waikato Bay of Plenty Magic 65 – 56.

[17] After improving her fitness throughout 2014, Pettitt was again selected in the Australian Diamonds squad, but failed to make the final team.

[18] In 2017, after being gone for three years, Susan Pettitt had returned to the Australian Diamonds and had a 57–50 victory over Silver Ferns and redeemed her MVP title.

[19] During the same game, Susan Pettitt was instrumental during her time on court for the first half, finishing with 10 goals out of 14 attempts, along with eight feeds before making way for Stephanie Wood at half-time.