You could argue that Father William Kelly was destined to become the pastor of St. Paul's one day, as the idea of becoming a priest first occurred to him when he was a fifth grader at the Boston Archdiocesan Choir School (now called the St. Paul's Choir School). On April 25, 2016, Fr. Kelly officially assumes the duties of pastor of the parish, senior chaplain of the Harvard Catholic Center, and head of, yes, the St. Paul's Choir School.

Fr. Kelly grew up in North Quincy, the oldest of six children. He attended B.C. High, and entered the seminary directly from there, followed by five years at the North American College in Rome. He was ordained in 1988 and assigned as parochial vicar briefly at Sacred Heart in East Boston, and then St. Paul's in Hingham. In 1996 he completed doctoral studies at the Gregorian University in Rome with the plan of serving as spiritual director and a teacher at St. John's Seminary in Boston, a position he held for ten years. During that time, he was on the staff of the Institute for Priestly Formation at Creighton University in Omaha, Nebraska, and on the board of the Federation for Seminary Spiritual Directors, for which he served as president for three years.

Fr. Kelly has lectured and led retreats throughout the United States. For five years he was Director of the Office for Clergy Support and Ongoing Formation for the Archdiocese of Boston. In May 2010, he was assigned his first pastorate, at St. Mary's in Dedham. And now, Fr. Kelly has returned to his roots in a sense, as the head of the school where he first had an inkling of his vocation to the priesthood. All for Jesus through Mary!