Born in Etterbeek, a suburb of the city of Brussels, Terlinden entered the seminary after graduating with a bachelor’s degree in commercial engineering, fulfilling a period of military service, and teaching for a short time in a high school.
He was ordained a priest a month before his 31st birthday in 1999 and proceeded to earn a doctorate in moral theology from the Alphonsian Academy in Rome. His thesis included a study of the writings of St. John Henry Newman.
The archbishop-elect’s priestly ministry has been marked by an attention to youth and young adults.
At his first assignment in a parish in Louvain-la-Neuve in 2003, he founded an Italian-style oratory for young people, and in 2013 in a Brussels suburb he co-founded a group for students and young professionals called “Pôle Jeunes XL.”
He spent nine years as the head of vocations for the archdiocese and was president of the French-language archdiocesan seminary, where he has also taught moral theology.
Terlinden told the Catholic Flemish magazine Kerk and Leven in 2021 that he had a profound experience as a young priest at World Youth Day in Rome in 2000. While he was in the military as a young man, he also took part in a military pilgrimage to Lourdes, France.