Balaș took up athletics owing to her caretaker Luisa Ernst, who was also a retired high jumper. In 1953 she transferred from Timișoara club "Electrica" to CCA (CSA Steaua). After finishing fifth in the 1956 Melbourne Olympics, she won Olympic gold medals at Rome in 1960 (becoming the first Romanian woman to do so) and Tokyo in 1964. At the 1964 Olympics she competed with a torn tendon, which forced her later to withdraw from the 1966 European Championships. Nevertheless, between 1957 and 1966, Balaș won 154 consecutive competitions, not including qualifying competitions or exhibitions. She improved the world record 14 times, from 1.75 m to 1.91 m, and equalled it once outdoors and once indoors. She was the first woman to jump over six feet. Her technique was a sophisticated version of the scissors technique.