Born in Mesa, Arizona, Stewart developed an interest in the southwestern U.S. and the environment that never left him.
The experience Stewart gained in the food industry would prove valuable when he returned to academia.
In 1951, Stewart joined the University of California, Davis faculty as chair of the Department of Avian Sciences (then known as Poultry Husbandry).
In 1959, Stewart returned to UC-Davis as chair of the Department of Food Science and Technology (FST) where he would serve until 1964.
Stewart returned to the FST department in 1970 as a teacher and researcher, including serving as coordinator of the Food packaging program from 1969 to 1974.