His first assignment was as Associate Pastor at St. John the Evangelist Parish in Butte, and to the faculty of Butte Central High School. In January of 1971, he was named the Chaplain of the Montana State Hospital at Warm Springs. His pastoral assignments include: the Cathedral of St. Helena, St. Anthony Parish in Missoula, St. Michael Parish in Drummond, St. John the Baptist Parish with its missions in Alberton and Superior, St. Joseph Parish in Libby with its mission in Troy. He took a leave to tend to family members while serving at Parishes in Naples and Fort Myers in the Diocese of Venice, Florida. He was appointed Pastor of St. Charles Borromeo Parish in Whitefish in 1991 and served there until he accepted Senior Status on August 1, 2004. As a Senior Status priest, Father Roman lived in Kalispell and assisted parishes in the Kalispell Deanery until his health no longer allowed.
Coulomb graduated in November 1761 with the rank of lieutenant en premier in the Corps du Génie. He worked at Brest and then at Martinique. While he was in Martinique he became seriously ill several times. The research he did in Richefort won him the double first prize at the academy in Paris in 1781. He became a resident in Paris. He found a wife there and raised a family. He wrote 25 scientific Momoirs at the Academy from 1781 to 1806. He also participated in 310 committee reports to the Academy. In 1787 Coulomb was sent to England to investigate hospital conditions in London. In 1801 he was elected to the position of the president of the Institute de France. By 1791, the National Assembly reorganized the Corps du Génie. Coulomb had to resign from the corps. He received an annual pension which was reduced by two-thirds after the Revolution. He returned to his research in Paris in December 1795, upon his election as member for physique experiméntale in the new Institute de France. Coulomb's last public service was as inspector general of public instruction from 1802 until his death. Coulomb's health declined precipitously in the early summer of 1806 and he died. Secondary accounts indicate that Revolution took most of his properties and that he died almost in poverty.