McClellan was a standout athlete at St. John's Preparatory School and Mount Saint Joseph College.
In 1925 he moved to St. John's Preparatory School in Danvers, Massachusetts, where he compiled a 31-2 record over two years.
He produced two All-Americans, Ed Wineapple (who also played for McClellan at Salem High) and John Krieger.
He resigned after the 1938 season because he refused to take a pay cut as part of the administration's decision to give more money to the football team at the expense of the basketball program.
[1][3] McClellan returned to college basketball in 1940 as the head coach of the St. Anselm Hawks.