When he was ten, his mother left the house tired of a violent husband, so since then Boeninger lived in pensions.

Then he was a member of the Instituto Nacional General José Miguel Carrera and later at the Alonso de Ercilla Institute in Santiago, belonging to the Congregation of the Marist Brothers, where he would finish the High School in 1941.

He studied civil engineering at the Pontifical Catholic University of Chile, obtaining his Bachelor of Arts in 1950.

From 1964 to 1969, Boeninger entered the State of Chile as Director of Budgets for President Eduardo Frei Montalva (1964−70).

During the military dictatorship −and still member of the banned Christian Democratic Party− Boeninger studied political science at the University of California, Los Angeles (1975).