Gibson played basketball at Penn State University, graduating in 1952. He began his head coaching career at Mansfield University of Pennsylvania in the 1956–57 season. In seven seasons, Mansfield posted a 102–37 win–loss record under Gibson. In April 1963, Virginia named him its men's basketball coach; at the time, the Cavaliers were struggling to compete in the Atlantic Coast Conference (ACC). Virginia was 8–16 in Gibson's first season as coach and did not win 10 games in a season until 1968–69. The Cavaliers lost in the ACC Tournament's first round (the tenth consecutive season Virginia had exited the tournament at that stage), and Gibson faced a "revolt" at the hands of his own players. They petitioned against Gibson, and met with Virginia's athletic director, a group of faculty, and Gibson himself. The university retained Gibson following the meetings, and the players' complaints were not mentioned in Virginia's statement to the press, though the Associated Press said they were related to "Gibson's tactics and handling of players."
After another 10-win season in 1969–70, the Cavaliers improved to 15–11 and 21–7 the next two seasons, and Gibson was selected as ACC Men's Basketball Coach of the Year for the latter campaign. In March 1974, he accepted an offer to coach at South Florida. Four months later, he had a heart attack and was hospitalized. Gibson recovered and his South Florida team had a 15–10 record in 1974–75. On July 23, 1975, he died of what was reported as a likely second heart attack.