Ernst Hinterseer grew up in Kitzbühel, the son of a farmer. After World War II he apprenticed as a carpenter but focused on skiing after finishing his schooling. His first major win was at Wendelstein in 1953, and he then won the 1954 Austrian Championship in giant slalom. He was named to the Austrian team for the 1954 World Championships in Åre, Sweden, but placed only 38th in slalom. After winning several races in 1954-55 Hinterseer made the 1956 Austrian Olympic team, placing sixth in giant slalom at Cortina d’Ampezzo. Injuries caused him to have some problems in the next several seasons but he recovered for 1959-60 and at Squaw Valley in 1960, won two medals, a gold in slalom and a bronze in giant slalom, which led him to be named Austrian Sportsman of the Year for 1960.
After the 1960 Winter Olympics Hinterseer turned professional and won the 1963 World Professional title. In 1967 he turned to coaching, leading the Austrian Ski Federation from 1974-76, during which time his son, Hansi, made the 1976 Olympic team. His grandson, Lukas Hinterseer, played football for the Austrian national team.