Glenn Thomas began drawing as soon as he could hold a pencil, and he later became the art editor for the Sterling High School annual. Following graduation he earned a scholarship to study art. He was a free-lance cartoonist for several Cleveland-based newspapers.During World War I, Glenn served in France as a cartographer. After the war he stayed in France to continue his art studies.He established a profitable illustration business in Chicago, and then moved to New York, where for 30 years he specialized in commercial illustrations. He worked primarily in watercolors producing dozens of life-like drawing for such prestigious companies as Goodyear, Maxwell House Coffee, Washington State Apples, U.S. Steel, and Havoline Motor Oil. At the age 96 he completed two paintings for the Sterling Schools Foundation—one of the original high school on Fifth Avenue and another of the “new” building on Fourth Avenue. Both of these illustrations have been used numerous times in Sterling Schools Foundation publications.