Lojze Peterle was born to a peasant family in the Lower Carniolan village of Čužnja vas near Trebnje. He attended the Novo Mesto Grammar School. In 1967, he enrolled to the University of Ljubljana, where he studied history and geography, and later also economy. During his student years, he started collaborating with the Christian left intellectual circle around the journal Revija 2000.
In the 1980s, he started working at the Institute for Urban planning of the Socialist Republic of Slovenia. In the mid 1980s, he was involved in several projects of trans-regional cooperation within the Alpe-Adria regional cooperation network.