Hay was scheduled to compete at the 1948 Summer Olympics in London, but was injured in training prior to the event. In 1950, she competed in the European Athletics Championships; in doing so, she became the first Scottish person to compete at the European Athletics Championships. She came fifth in the individual 100 metres event, and was a member of the gold medal winning Great Britain 4 x 100 metres relay team. In the same year, she won the women's 100-yard dash event at the Edinburgh Highland games.