At the 1968 Olympic Games in Grenoble , France , he reached 24th place in the giant slalom. Shortly thereafter, on March 10, 1968, he won his first points in the Alpine Ski World Cup when he reached fifth place in the giant slalom in Méribel . At the end of the 1968 season he finished 35th in the overall World Cup ranking and 18th in the giant slalom ranking. On January 5, 1970, Heckelmiller took second place in Adelboden for the first time on the podium in a World Cup race. At the Alpine World Ski Championships in 1970 in Val Gardena , he came 11th in the giant slalom. In the following season 1970/71 he was able to improve his performance further and in the end reached 16th place in the overall World Cup ranking and 6th place in the giant slalom ranking. He started again at the 1972 Winter Olympics in Sapporo , but was eliminated in the first run. On April 15, 1972 he won a giant slalom at the “Silvretta-Tropäe” in Ischgl ahead of the Austrians Hubert Berchtold and David Zwilling , and the next day in another giant slalom, he came third behind Berchtold and Reinhard Tritscher .
In 1974 he became German champion in giant slalom. At the Alpine World Ski Championships in St. Moritz in the same year , he finished 11th again, as in 1970. He won his last World Cup points in March 1973.
After the end of his active career, he worked as director of a ski school in Oberjoch and as a hotelier.