Stewart was employed as trainee teacher at Warrnambool State School, then taught at Charlton then Benalla.
He entered Ormond College, University of Melbourne, where he graduated in philosophy in 1906 with first class honours, winning the Hastie Scholarship in Logic and Philosophy[2] and from 1907 to 1909 was employed delivering lectures in Logic and Philosophy to Ormond College students,[4] meanwhile studying theology and was ordained a minister of the Presbyterian Church.
He was heavily involved with the University Union, the controversial[2] Public Questions Society, and the Student Christian Movement and served as chairman of each.
[4] in 1920 Stewart was appointed associate professor of philosophy, a post created for him, then in 1922 was offered the Hughes Professorship in Philosophy on the recommendation of Professor Mitchell,[5] the outgoing incumbent, and was appointed the following year.
[7] Stewart married Margaret Grace "Madge" Bothroyd ( – 13 August 1948) on 3 November 1909.