A tall and lean swimmer known for her elegant technique, Leech started swimming as a child to build strength after a series of stomach disorders in her infancy.

Leech's preparation was hindered by illness, which forced her out of the 1956 Australian Championships, but she recovered to gain Olympic selection in both the 100-metre freestyle and the corresponding relay.

Leech retired after the Olympics at the age of 15; she cited anxiety caused by racing as one of the main factors in her decision.

[2] A delicate child, Leech had an aversion to eating in the first two years of her life, so her mother fed her in small hourly doses.

Conventional medicine failed to rectify Leech's dietary issues, so her mother put her on a fast for ten days at the recommendation of a naturopath.

[3] In an effort to help her gain muscle control and confidence, her parents sent her to start ballet dancing, before trying swimming, a sport her mother had competed in.

[2] Living in Bendigo and studying at Camp Hill Primary School,[3] Leech could only travel three times a year to train with Froelich, so she relied heavily on dry land simulations, such as a pulley attached to the kitchen door.

[5] From 1954, Leech attended St. Michael's Girls' Grammar School and trained with Froelich on a daily basis at the City Baths.

[7] She proceeded to the Australian Championships, winning the 110-yard freestyle in 1 minute 7.6 seconds to become the youngest ever winner of an open title at the age of 13.

[7] Leech's regimen differed from most swimmers because Froelich was not an advocate of distance training, and designed shorter workouts for his students.

Froelich did not push her to continue swimming laps when she felt tired, but emphasised an efficient stroke mechanism, which Leech implemented with a long and graceful arm action.

Leech stood 180 centimetres (5'11"), but weighed only 57 kg (126 lb), with broad shoulders, slim hips and large hands and feet.

Spinal problems caused by a back misalignment prevented her from using the optimal flip turn preferred by freestyle swimmers.

[7] Having arrived at the Olympics, Leech made her debut in the 100-metre freestyle, an event in which she, Fraser and Crapp were regarded as the three strongest competitors,[7] although the latter two were considered to be substantially stronger.

With 25 metres left, Morgan took her head out of the water, and seeing the American a body length in front, dug deep to re-establish a lead of 0.7 of a second going into the final changeover.

[10] The Melbourne Olympics was the only time that Australia has made a clean sweep of the 100-metre freestyle and the relay events for both men and women.

[1] Leech married Mitch Tuohy and had two sons,[1] Adam and Troy,[16] whom she discouraged from entering competitive swimming, fearing the pressure and strain of racing.

[16] In February 2003, Leech phoned quadruple Olympic champion Betty Cuthbert to comfort her during her recovery from a brain hemorrhage.

[18] In October 2006, Leech combined with 1956 teammate John Devitt to launch "50 Years On—The Melbourne Olympics", a series of stamps from the Australia Post.