Stephanie began training for serious competition in 1967, and would have qualified to attend that year’s Pan Am Games if she had been old enough. The following year, at age 15, she became the youngest member of the 1968 Canadian Olympic team that competed in Mexico City. In her peak year of 1971 Stephanie toured Europe, won all her events despite suffering from back strain, and was credited with “winning on courage”.

Stephanie was a member of the 4×100m relay team at the 1968 Olympics in Mexico City and she set a junior record for her leg of the relay with 11.7 sec. She also won gold for the 100m with 11.6 sec at the first Canada Games, held in Halifax in 1969.

She captured bronze in the 100m and silver at the 4×100m relay at the 1969 Pacific Conference Games and won gold as a member of the 4×100m relay team at the 1969 World Cup in Stuttgart, Germany.

Furthermore, Stephanie was a member of the Canadian 4×100m relay team that won bronze at the 1970 Commonwealth Games in Edinburgh and set a new Canadian record of 44.6 sec. At the 1971 Pan Am Games in Cali, Columbia, she captured gold in the 200m with a Pan Am Games record time of 23.5 sec and earned a silver in the 100m events.

In 1971 Stephanie was ranked #1 in Canada for the 100m and 200m, sixth in the world for the 200m, and ninth in the world for the 100m. She also competed on a European tour, winning all her events. In 1972 her training was interrupted by a recurring leg injury. Following a brief comeback in 1975, she retired from active competition.