Cheryl Gibson joined the Canadian national swimming team in 1974 and, one year later, became the national champion in the 400 metre individual medley. She first represented her country abroad at the 1975 World Championships and, shortly after, won her first international medals at that year’s Pan American Games: silver in the 200 metre butterfly and the 400 metre individual medley and bronze in the 200 metre backstroke and individual medley. Her next stop was the 1976 Summer Olympics, where she won a silver medal in the 400 m individual medley, behind Ulrike Tauber, who shattered the world record by over six seconds (Gibson’s performance also broke the world record, but “only” by just under seven-tenths of a second). Tauber was later revealed to have been involved in doping for the majority of her career, and many consider Gibson to have been the true winner of the race. She also placed fifth and sixth in the 100 metre backstroke and the 200 metre butterfly respectively, in addition to being eliminated in the opening round of the 200 metre backstroke. That year she won the Velma Springstead Trophy as Canada’s outstanding female athlete.
Gibson’s next major stop was the 1978 Commonwealth Games, where she won the 200 m backstroke and took bronze in the 100 m version and the 400 m individual medley. Later that month she captured bronze in both the 100 and 200 m backstroke events at the World Championships. She followed this up with three silver medals at the 1979 Pan American Games in the 100 and 200 m backstroke events and the 4x100 m medley relay (alongside Gail Amundrud, Nancy Garapick, and the non-Olympian Anne Gagnon). Her final major international tournament was the 1982 Commonwealth Games, where she earned gold in the 4x100 m medley relay (with Michelle MacPherson, Maureen New, and Anne Ottenbrite), silver in the 200 m individual medley, and bronze in the 200 m backstroke.
Gibson retired from active competition in 1982, the same year that she graduated from Arizona State University. She became a chartered accountant in 1986 and earned a law degree from the University of Toronto in 1989. As of 2013 she is a partner with Fraser Milner Casgrain LLP and has been heavily involved in sports administration. In addition to the many Canadian and Commonwealth records that she earned over her career, as well as her 34 national titles, she has accrued numerous honors, including induction into the Alberta Sports (1986), Edmonton Sports (1991), Arizona State University Sports (1996), Canadian Olympic (2001), Swim BC (2005), and British Columbia Sports (2010) Halls of Fame.