Rosheehan graduated from a combined Bachelor of Forensic Science / Bachelor of Laws (First Class Honours) degree from the University of Canberra in 2009. During her degree she undertook studies in employment law and industrial relations. In 2009, Rosheehan was the recipient of the ACT Women Lawyers Award for excellence throughout her law degree.

Rosheehan joined Harmers in 2008 as a summer clerk and returned as a graduate-at-law in February 2010. Rosheehan will be admitted as a solicitor in 2010.