O'Sullivan made her debut in the State Basketball League (SBL) in 2011 for the Perth Redbacks. In 2013, she moved to the United States to play college basketball for the College of Coastal Georgia (CCGA). She spent three seasons at CCGA, graduating in 2016.[1] During this time, she continued to play in the SBL for the Redbacks.[2][3] In 2017, she joined the Perry Lakes Hawks and won an SBL championship.[4] Her final season in the SBL with the Hawks came in 2019.[5]
Football career
Upon returning to Australia after graduating from CCGA, O'Sullivan was intrigued by the hype surrounding women's football and was convinced by her father John to play for East Fremantle – the club he represented in league football on 133 occasions.[6] She impressed for the Sharks, and as a result, her name made its way to Fremantle women's head coach Michelle Cowan. O'Sullivan was recruited by Fremantle as a pre-draft rookie selection,[6] and made her debut in a thirty-two point loss to the Western Bulldogs at VU Whitten Oval in the opening round of the 2017 season.[7] She played every match in her debut season to finish with seven matches.[8]