Son of Warren P. and Anna D. Knowles, Knowles was a 1926 graduate of River Falls High School (side note Warren P. Knowles Sr., was an 1897 graduate of RFHS). During his high school days Knowles was a standout athlete both on the football field and basketball court. During his senior year of high school, his team won the 1925 Wisconsin State Football Championship and placed second in the Wisconsin State Basketball Tournament losing to Stevens Point in the lowest scoring championship game in the State's history, 9–7. He was recognized in the River Falls Wildcat Athletic Hall of Fame with a Distinguish Citizen Award.