She began swimming at the age of 9, while she and her sister spent two years at the Ursuline Convent boarding school in Santa Rosa.

[4] In 1944, at age 18, she became the first woman, as well as the first swimmer, to receive the coveted James E. Sullivan Award, recognizing her as the outstanding American amateur athlete of the year.

[4] Curtis competed at the 1948 Summer Olympics in London, England, winning a medal in every freestyle swimming race in which women were allowed to enter at the time.

"[2] However, her favorite moment of the Games came during the third event, when she won her second gold medal as a member of the women's 4×100-meter freestyle relay team.

When she took the water for the anchor leg in the relay, the United States team was in third place; she passed Johanna "Hannie" Termeulen of Holland and then Fritze Carstensen of Denmark to win the gold medal for the US by four-tenths of a second, setting another Olympic record in the process.