Dr Cassar is a highly qualified professional, having earned postgraduate and master's degrees in management and Religious Studies from Sheffield Hallam University. 

Her career commenced in the manufacturing sector, where she gained managerial experience and expertise in industrial relations. With over a decade in the tourism industry, she progressed to top management roles, specializing in human resources management.

Beyond her corporate journey, Dr Cassar delved into the social sector, overseeing the establishment of the first female residential program for drug users with Caritas Malta. Joining the Public Service in 2013, she served as Director General Human Resources for the Ministry of Health, later assuming roles in implementation and, eventually, becoming Permanent Secretary of the Division for People and Standards within the Office of the Prime Minister in 2017. 

Dr Cassar's career showcases her dedication to organizational development, leaving a lasting impact on human resources, standards, and training within the government sector.