[2] After displaying an interest in the priesthood, Williams was sent by Bishop Benedict Joseph Fenwick to study at the Sulpician College in Montreal in 1833.

He served in this capacity for ten years, also teaching Sunday school and catechism classes.

[2] He was rector of the cathedral from 1855 until 1857, when he became pastor of St. James Church in the same city, where in 1842 he established the first Conference of the Society of St. Vincent de Paul in New England.

[1] In addition to his pastoral duties at St. James, Williams was named Vicar General of the Diocese of Boston in the summer of 1857.

He administered the affairs of the diocese during the final years of Bishop John Bernard Fitzpatrick, whose health was in decline.