"He was a real explorer as a child, he used to take his bicycle apart and put it back together again," said his father, Richard Keller.
In his work, David Keller advocated for philosophers, scientists and policymakers to work together for environmental stewardship, said Brian Birch, associate vice-president for academic affairs at UVU.
"David was a public intellectual," Birch said, participating in debates like "Is God necessary for ethics?" His own opinions, though, weren't the subjects of his university lectures.
"He always said it wasn't his job to convince his students of his point of view, but to give them a broad understanding of various points of view," said Richard Keller. In his 18 years at UVU, David Keller brought lofty ideas down to earth, said philosophy professor Elaine Englehardt.
"He helped students understand the most difficult of philosophical ideas," she said. "He had the ability to explain simply what he was trying to say."
As director at the Center for Ethics, David Keller attracted speakers ranging from Ralph Nader to Sen. Mike Lee, R-Utah.
"I just feel like David created one of the stellar programs in the country," Englehardt said. The high-profile visitors often stayed to give students advice. "I think he helped the rest of the university grow up," she said.
Keller also founded a chapter of the American Association of University Professors union one that now bears his name advocating for professors and bringing attention to the issue of low-paid adjuncts while maintaining a good relationship with the UVU administration.
"They respected David and his analysis of a situation. He didn't do anything outrageous or unfair ... and was clear-minded," Englehardt said. "When David made a friend, he kept that friend. He really had good ideas."
Keller is survived by his wife, Anina Merrill, brother Peter Keller and sister Christene Keller-Ensign. Funeral arrangements are pending.