Ellis began his career working as an assistant professor of chemistry at the University of New Hampshire, a position he held from 1962 to 1967.
[4][5] On March 4, 1978, Ellis was selected by the trustees of Lafayette College to become the school's 13th president.
[6] He was inaugurated on October 20 of that year and subsequently received letters of advice from many individuals, including president Jimmy Carter who wrote, "you bring to Lafayette an admirable leadership ability and a special sensitivity to the challenges now facing American higher education...
The money raised in this effort went largely towards the construction of several buildings on campus,[8] one of which being a $16 million student center which required a controversial removal of a pre-World War 1 fraternity house.
"[11] In 1989, Ellis attended a six-week Advanced Management Program at Harvard Business School, and the following year became the president and director of the Museum of Science in Boston, Massachusetts.