Dcn. Asselin has been assigned to St. Elizabeth Parish since his ordination to the diaconate in June 2019. Dcn. Asselin serves as the Spiritual Advisor to the St. Elizabeth Conference of the St. Vincent de Paul Society and assists at the St. Camillus Food Pantry. He was elected to his first term on the Archdiocesan Deacons Council in 2022 and serves on its Continuing Formation Committee. Dcn. Asselin has been a Deacon Affiliate of the Paulist Fathers since 2022.

He received his bachelor’s degree from the University of Vermont in 1980. After spending a few years in the Society of Jesus, he earned master's degrees in fine arts history from the University of Colorado in Boulder and in Asian languages and literature from the University of Washington. He was granted a Ph.D. in Asian languages and literature (Chinese) from the University of Washington in 1997, and has published in the field, including a book on ancient Chinese literature, history, and culture in 2010. Dcn. Asselin later completed the five-year diaconate formation program of the Archdiocese of Washington. He has been employed at the National Security Agency since 2000, currently serving as its Training Director and as the Commandant of the National Cryptologic University.

Dcn. Asselin is married to Son Vuong, a State Department architect; they have an adult daughter, Sydney, a lighting designer in Los Angeles. Their family has been members of the parish since 2000. Born in Maine, Dcn. Asselin grew up in St. Mary of the Nativity Parish in Scituate, Massachusetts, and in St. John the Evangelist Parish in Northfield, Vermont.