A realist-style artist, Gummo most often painted landscapes, portraits, and still-lifes, usually with oils. Much of his imagery was inspired by the north-central Pennsylvania countryside and the Susquehanna River.
His arrival as a faculty member made it possible for Bucknell to offer art as a major for the first time. He taught at Bucknell from 1931-1974. Gummo, who died in 1986, was posthumously presented the Academy of Artistic Achievement Award by Bucknell for his lifetime contributions to the arts in March 2002.