Mr. Ellingson served as the president of the Institute from 1936-1969. He was also an economics professor and wrestling coach. In 1944, he was instrumental in the name change of the Rochester Athenaeum and Mechanics Institute to Rochester Institute of Technology, reflecting the focus on technical education that had developed over the years.

Mr. Ellingson not only led RIT during a period of sharply increasing enrollment, but he also expanded the downtown campus. In 1937, he was a driving force behind bringing the Empire School of Printing to RIT.

In the 1960's, President Ellingson led the campaign for RIT to be considered as a home to the newly developed National Technical Institute for the Deaf. He saw a great value to RIT hosting such an institute and he pursued it ardently.