[2] Dubois was ordained a priest for the Archdiocese of Parish on September 22, 1787, by Archbishop Antoine-Eléonore-Léon Le Clerc de Juigné.

He was carrying a letter of introduction from the Marquis de Lafayette, a French hero of the recently concluded American Revolution.

The Richmond families hosted Dubois until he was able to rent a house in the city and open a school to teach French, the classics and arithmetic.

That same law also guaranteed freedom of religion, releasing the Commonwealth's small Catholic population from civil restrictions.

On one occasion, the Virginia General Assembly invited Dubois to celebrate mass in the Capitol courtroom.

During his time in Richmond, Dubois celebrated masses in rented rooms or at the homes of the city's few Catholic families.

He was also responsible for the church presence in the Shenandoah Valley of Virginia and the frontier regions westward to the Mississippi River.

The Society of Jesus had previously supervised missions in these areas, but Pope Clement XIV had suppressed the order in 1773, forcing them to surrender all their holdings.

For the next eleven years, Dubois served as pastor of St. John the Evangelist Church, making excursions into the frontier.

[8] Dubois was consecrated at the Cathedral of the Assumption of the Blessed Virgin Mary in Baltimore by Archbishop Ambrose Maréchal on October 29, 1826.

At one point, the trustees of St. Patrick's Old Cathedral in Manhattan, tangled in a dispute with Dubois over the ownership of church property, withheld their contributions of food and shelter from him.

[10] Dubois ordered that the diocesan pastors direct all church collections on Christmas Day to the care of orphans.