From the age of twelve, when she set eleven records in her age group at one meet, Allison Higson was known as a record-breaking swimmer. In 1986 she took the 100 and 200 metre breaststroke titles at the Commonwealth Games, in addition to a silver medal in the 4x100 metre medley relay (alongside Jane Kerr, Donna McGinnis, and the non-Olympian Barbara McBain), and then went on to win bronze in the 200 m breaststroke at the World Championships, behind Silke Hörner of East Germany and Tanya Bogomilova-Dangalakova of Bulgaria. In both tournaments she earned the distinction of being the youngest medalist ever and, in the latter, she was the only Canadian woman to reach the podium. She followed up these accomplishments by winning four medals at the 1987 Pan Pacific Championships: gold in the 100 m breaststroke, silver in the 200 metre individual medley and the 4x100 m medley relay, and bronze in the 4x200 m freestyle relay. Her next stop was the 1988 Summer Olympics, where she won a bronze medal in the 4x100 m medley relay (with Kerr, Keltie Duggan, Lori Melien, Patricia Noall, and Andrea Nugent) and placed fourth, sixth, seventh, and seventeenth in the 100 m breaststroke, 4x100 m freestyle relay (alongside Kerr, Noall, Nugent, Kathy Bald, and Kristin Topham), 200 m breaststroke, and 200 m individual medley respectively.
After the Games, the pace of Higson’s career began to ease, although she won silver in the 4x100 m freestyle relay at the 1990 Commonwealth Games, with Noall and the non-Olympians Erin Murphy and Kimberley Paton. Her final major international tournament was the 1992 Summer Olympics, where she was eighth in the 4x100 m freestyle relay (alongside Nugent, Nikki Dryden, and Marianne Limpert) and 22nd and 25th in the 200 and 100 metre freestyle events respectively. After the Games she accepted a scholarship at Stanford University and swam there from 1992 through 1997 while earning a degree in psychology and human biology. Since then she has worked as a manager and business partner at several major corporations, the most recent of which (as of 2013) is Google. She has been inducted into the City of Brampton Sports (1986) and Ontario Aquatic (1998) Halls of Fame.