MA Glas 1900, MB ChB 1905; DPH Camb 1908.
Stewart gained his medical education in Glasgow and held resident appointments at Glasgow Eye Infirmary and the Royal Hospital for Sick Children, Glasgow. He was medical inspector of schools for Lancashire County Council from 1909 until 1913 when he was appointed consultant tuberculosis officer for the Council. Stewart pioneered the use of x-ray work and artificial light treatment in the context of tuberculosis, and he wrote a number of articles on these subjects. He was a fellow of the Society of Medical Officers of Health and a member of the Tuberculosis Society.