Cahill coached Army football for eight seasons, composing a recording of 40-39-2, which ranks fifth on the academy's career wins list. In his first season at the helm, Cahill improved Army from a 4-5-1 win-loss record in 1965 to an 8-2 record in 1966, which led him to be named National Coach of the Year by the American Football Coaches Association, the Football Writers Association of America and Touchdown Club of Washington, D.C. He became the first coach to win the FWAA award in their first season as a head coach. He posted a 5-3 record against Navy.
