The University of Tulsa, where Fanning had worked in the athletics department for 13 years, confirmed his Sunday death. Cause of death was not revealed.
"We are saddened by the news of Mike's passing," athletic director Rick Dickson said in a statement Monday. "He was a tremendous football player at Notre Dame and in the NFL and carried that competitiveness and work ethic into everyday life. He was such a likeable person who worked to help TU athletics achieve success."
A Tulsa, Okla., native, Fanning went on to star at Notre Dame, making 164 career tackles. The Los Angeles Rams made him the ninth overall selection in the 1975 NFL Draft, and he earned all-rookie team honors that season.