Mr O’Callaghan, who was 74, died suddenly at Kerry General Hospital on Wednesday morning.
He owned and operated the Fáilte Hotel in Killarney, one of the most popular live music venues in the town, and was a prominent member of the Vintners Federation of Ireland.
Mr O’Callaghan was elected to Killarney Town Council in 1979, holding his seat until the 1999 local elections. He was elected as a member of Fianna Fáil, but later severed links with the party and became a close political ally of former independent TD Jackie Healy-Rae.
He served for a term as a director of the board of Fás and played an active role in the Cork/Kerry Tourism organisation. He was also a found-er member of the Killarney Tour-ism Council.
The late Mr O’Callaghan was also president of Killarney Celtic FC and had a lifelong interest in sports, particularly horse racing. He was the owner of the legendary horse Colonel James.
The annual general meeting of Killarney Celtic, set to take place last night, was postponed as a mark of respect.
Mayor of Killarney Seán Counihan said Mr O’Callaghan was a very tenacious councillor who was never afraid to speak his mind. “He always had the best interests of Killarney at heart and he was very active in promoting events that brought people to town,” Mr Counihan said.
Mr O’Callaghan is survived by his wife, Eileen, and six sons, Micheal, Colm, Paudie, Dermot, Donal and Niall.