He was active in band, orchestra, chorus, biology club, freshman football, and was in the National Honor Society.
By the time he graduated from high school, he had saved $252.50 for college by shining shoes for 15 cents per pair at the Savery Hotel in Des Moines.
Hubbard was appointed as research engineer in July 1947, making him the first black faculty member at the University of Iowa.
In 1971 he was named Vice President of Student Services, becoming the first black vice-president at a Big Ten university.
As a memorial to him, the field next to the Student Union on the University of Iowa campus was renamed Hubbard Park on December 6, 1991.