Toh held several Cabinet portfolios in pre- and post-independence Singapore, including Deputy Prime Minister (1959–68), Minister for Science and Technology (1968–75) and Minister for Health (1975–81). He served as the University of Singapore's Vice-Chancellor from 1968 to 1975. His stint at the university drew mixed reactions from staff and students. While his role to reorient the university's focus to suit the fledgling nation's needs was applauded, he was perceived as authoritarian, when he clamped down on student demonstrations and political activities.