Pat McMahon of County Clare, Ireland came to OBU as a distance runner and left OBU as a running legend. He is the only male OBU runner to win the NAIA National Cross Country Championship individual title, and he did it twice, 1965 and 1966, the latter in a record of 19:53.6 for the four mile event—a record which still stands. He finished fourth in the national cross country meet in 1967 and fourteenth in 1968. McMahon won four NAIA cross country All-America awards.

In outdoor track, McMahon placed third in the 3,000-meter steeplechase in the 1967 NAIA national championship meet and won that event in 1968 in a time of 9:26.7. He won outdoor All-America recognition in 1967 and 1968. In 1966 he captured the 10,000 meter event at the Kansas Relays. In the Oklahoma Collegiate Conference meet, he won the mile and two mile runs in 1966; the 2 mile in 1967; and tied for first in the mile and won the two mile in 1968.

Records he established while at OBU include a 9:02.0 in the two mile; 13:52.8 in the three mile; 19:11.0 in the four mile (cross country); 28:53.4 in the 10,000 meters; 29:00.6 in the 6 mile (cross country); 2:19:49.7 in the marathon; and 9:18.7 in the 3000 meter steeplechase. His OBU marathon time remains as a school record. 

McMahon ran the marathon for Ireland in the 1968 Mexico City Olympics, finishing twelfth in 2:29:21. In the historic Boston Marathon, he finished third in 1970 in 2:14:53 and second in 1971 in 2:18:50, just five seconds behind the winner.

McMahon is a retired teacher and coach and lives in Maynard, Massachusetts.