Thomas married to Cathie (née Harvey) and had two sons and a daughter and three grandchildren. His interest in Irish, and particularly O'Dubhda history resulted in his being one of the first members of the O'Dubhda Clan Association in 1990, and he has attended every rally since. In 1997, he was chosen as the Taoiseach-elect when the Chieftainship was restored, and in September 2000 was inaugurated with Brehon rites at Cahir Mor as The O'Dubhda – the first chief in over 400 years. At the same meeting, Richard F Dowd of New Jersey was chosen as the Tánaiste. During his period in office he has represented the clan at the 1798 Bicentennial celebrations and at the unveiling of the memorial to Baron James O'Dowda, while at the same time making efforts to contact O'Dubhda clansmen worldwide. In September 2003, he handed the white staff of office, the O'Dubhda standard and the Chief's personal pennant to his successor, Richard F. Dowd.