Mickey O’Brien went to work for the University of Tennessee in 1938 – just in time to help with three successive unbeaten seasons and trips to bowl games. He served as a jack-of-all-trades for the Vol program. In addition to being head athletic trainer for all sports teams, he was in charge of the training table, oversaw the equipment and laundry operations, and served as chief recruiter in Chattanooga, North Carolina, and Florida.
O’Brien was designated Trainer Emeritus in 1977 for the Volunteers’ football team and served under five football coaches at Tennessee, beginning with Gen. Bob Neyland. Experts in sports medicine regarded O’Brian as one of the premier college athletic trainers. He served as a mentor to various athletic trainers including NATA Hall of Fame members Jim Goostree and Chris Patrick. He helped form the Southeastern Conference Trainers Association and served as its first President. He died October 24, 1986 in Knoxville, Tennessee at age 79.