Born in Bergamo, Tremaglia grew up assimilating the ideas of the Italian fascism in his childhood and adolescence.

[1] During World War II, at the age of 17, he fought in the National Republican Guard belonging to the Italian Social Republic, a puppet state controlled by Nazi Germany.

[3] After the post-war period, Tremaglia enrolled at the Catholic University of Milan but was kicked out of it when his past as a National Republican Guard volunteer was discovered.

Tremaglia died at his home in Bergamo after a long distress with Parkinson's disease.

[4] Tremaglia found himself at the center of a controversy for defending the well-known anti-homosexuality Roman Catholic colleague Rocco Buttiglione after the 2004 European Parliament election.