Pilarz graduated from Camden Catholic High School in 1977. He received a bachelor's degree in English from Georgetown University in 1981, although he had initially enrolled at Georgetown with the intention of studying politics. Pilarz became interested in the priesthood as an undergraduate student at Georgetown and put together a plan to join the Jesuits during his senior year. Pilarz elaborated on his interest in a 2010 article in the "Milwaukee Journal Sentinel", "I remember going into the library, sneaking into the stacks, looking at books about Jesuits. I wouldn't want all my friends to know I was thinking about this. It was kind of an impulse thing at the time...I thought I'd give this a shot and I did...And it felt right all the way along." Pilarz told his family of his decision to join the Jesuits after dinner at their home in Voorhees, New Jersey. He first entered the Society of Jesus in August 1981 and was ordained a Catholic priest within the Jesuit order in 1992.