Erastus W. Pennock was born in Chicago and went to school in Pennsylvania before attending Springfield College (then called the International YMCA College), where he graduated in 1914. Pennock completed his graduate work at Springfield College, Columbia University, and Kentucky University. After graduating, he served in the United States Army Field Artillery. After World War I, Pennock taught physical education, first at a YMCA and then at the Peabody High School in Pittsburgh, Pennsylvania. In 1925, he became a faculty member at his alma mater, where he taught physical education and coached wrestling, football, and track and field. During World War II, he took a leave of absence from the college to serve in the Surgeon General’s Office of the War Department. In 1959, Pennock was awarded Springfield College’s Tarbell Medallion Award, which is presented to alumni who have given meritorious service to the college.