He assumes the role after a distinguished playing and administrative career in Ulster and Irish rugby.
A retired 67-year-old teacher at Larkfield Secondary School, Belfast, the new President lives in Lisburn, County Antrim and is married to Mabel, with a son Joel, a former Irish Schools international, and daughter Clare.
A native of County Armagh and a former pupil at Larne Grammar School, John Callaghan played rugby as a notable second row or back row forward with King's Scholars Teaching College, Queen's University and CIYMS.
But he spent most of his playing and coaching career with CIYMS in a halcyon period during the late 1960s and early 1970s when he lined out alongside such notable Irish international players as Cecil Pedlow, Ken Kennedy, Brian Marshall, Eddie Grant, Ronnie Hakin and Paddy Agnew.
A highlight of that period was the winning of the Ulster Senior Cup in 1966.
Elected to the Ulster Branch in the 1989/90 season as the delegate from Armagh Rugby Club, he was Ulster Branch President in the landmark season of 1998/99 when Ulster won the European Cup.
He joined the Committee of the IRFU in the 2000/01 season and has been a member of various sub-committees, most notably contributing in the vital age grade area where he has had a significant part to play in the promotion and new structuring of Irish youth rugby.