Lech blossomed into a ski resort while he was growing up, and his family converted their farm house into a pensione.

His childhood coincided with the post-World War II poverty of Austria, so not only did Zimmermann have no formal training, but his skis were often "fourth or fifth-hand.

Zimmermann returned to Austria by the time he reached 18, and won a clean sweep of the 1958 Junior Championships.

Zimmermann won two medals at the 1962 World Championships in Chamonix, a gold in the giant slalom and a bronze in downhill.

Despite not sweeping the alpine events as did his compatriot Toni Sailer in 1956, Zimmermann appeared on the 10 February 1964 cover of Sports Illustrated magazine in the United States.