John Leo Dorn was born on May 1, 1942, in Highlandtown, Baltimore, Maryland. He attended St. Brigit and Sacred Heart of Jesus parishes and went to Calvery Hall College High School. He then attended the John Hopkins University to study electrical engineering from which he graduated in May 1975. Before joining the Trinitarian Order, John worked for Social Security and the C & P Telephone Company. He subsequently attended St. Mary's Seminary in Roland Park and the Washington Theological Union in Silver Spring, joined the Trinitarian Order, and was professed a Trinitarian in April 1981.
John Leo Dorn was ordained on August 15, 1981. As a Trinitarian, he served variously as teacher, provincial secretary, provincial treasurer, member of the provincial council and development director. In July of 1993, he was named Provincial of the Order. At the start of his leadership role, the Trinitarians celebrated the 800th anniversary of the founding of the Order (in 1193 by St. John DeMatha, O.SS.T.) and Fr. John traveled to Paris for a world-wide meeting of the superiors of the order.
Following this, and after a short period of residency at St. Lawrence Martyr Church with duties at the Monestary in Pikesville, he was named Administrator of the Parish by the Cardinal Archbishop Keeler until he completed several Trinitarian projects and was named Pastor in August 2002.
Before retiring in 2010, he was the Associate Pastor in 2009.
Sadly, he passed away on March 7, 2015.