Despite his lack of practical farm expertise, William Johnston (1848-1885) was the "founder" of the Ontario Agricultural College and its Principal from 1876-1879. It was his vision that led to the creation of a three-year degree program, affiliated with the University of Toronto, which began in 1887 and continued until 1964. Johnston Hall, built in 1932 as a student residence and administrative offices, is now one of the University's most recognized buildings.

Johnston Hall's stone tower is the University of Guelph's best-known landmark, and its spacious front lawn one of the most loved spots on campus. Administrative offices fill the lower floor, while 315 students live on the top three floors in large double and triple rooms. Built in 1932, Johnston Hall's traditional architecture and its spacious tower lounge make it a favorite with many students.