Representing Czechoslovakia, he won the gold medal in the featherweight division at the 1952 Summer Olympics in Helsinki.

Zachara was born on 27 August 1928 in the village of Kubrá, which is now a part of the city of Trenčín,[1] in a family of factory workers.

Nonetheless, he was not allowed to compete at the 1948 Olympics, because another boxer, who was a Communist party member, was given preference.

Nonetheless, Zachara got his revenge at the 1952 Summer Olympics in Helsinki, where he won a gold medal after defeating Sergio Caprari in the finals, despite being considered an underdog.

After ending active boxing career, he settled in Dubnica nad Váhom, where he trained young boxers before retiring from the sport.