In 1945, he enrolled in the College of Pharmacy at Howard University in Washington, D.C., where he earned a Bachelor of Science degree in 1950.
After qualifying as a registered pharmacist in Detroit, Michigan, he joined the United States Army and was assigned to FranMort-Hoechst and to Munich.
On October 2, 1957, Thomas converted to Catholicism and was received into the Catholic Church at St. Peter's Cathedral in Erie, Pennsylvania.
He began his studies for the priesthood in 1982 at St. Vincent de Paul Regional Seminary in Boynton Beach, Florida.
The Diocesan Consulters of the Diocese of St. Thomas unanimously elected Thomas to serve as Diocesan Administrator, a post he filled from August 11, 1992, until he was named as the Third Bishop of the Virgin Islands on October 30, 1993.