 Like Sherman Minton , Clarence Thomas was not a Catholic at the time he was appointed to the Court . Thomas was raised Catholic and briefly attended Conception Seminary College , a Roman Catholic seminary , but had joined the Protestant denomination of his wife after their marriage . At some point in the late 1990s , Thomas returned to Catholicism . In 2005 , John Roberts became the third Catholic Chief Justice and the fourth Catholic on the Court . Shortly thereafter , Samuel Alito became the fifth on the Court , and the eleventh in the history of the Court . Alito 's appointment gave the Court a Catholic majority for the first time in its history . Besides Thomas , at least one other Justice , James F. Byrnes , was raised as a Roman Catholic , but converted to a different branch of Christianity prior to serving on the Court . 
