He was ordained in May 1847. Returning to Ireland for a short time he was appointed a Professor in Carlow College. Croke's brother, James, was also a priest and served in the Pacific Northwest helping to found several churches including St. Joseph's Catholic Church in Oregon Territory.Wilfrid S.J. Schoenberg (1987 ) A History of the Catholic Church in the Pacific Northwest 1743 – 1983, The Pastoral Press Washington D.C. pp. 140–142 The Irish radical William O'Brien said that Thomas Croke fought on the barricades in Paris during the 1848 French Revolution. Croke returned to Ireland and spent the next 23 years working there.
