John was born in Dublin on 19 May, 1939. His father, a native of Limerick, was a member of the Gardai Siochanna (Irish Police Force) stationed in Dublin. John went to school to the local Christian Brothers in Marino. He began to take an active interest in music when he was about twelve years old. Careful scrutiny of a school photograph taken at that time shows four members of the music class who have made music their careers with varying degrees of success. They are: John himself, Paddy Moloney of the Chieftains, and Leon and Liam Rowsome, sons of a very famous father.
John's hobbies include tinkering with cars, home improvement and decoration, gardening and latterly cooking — an art for which he had a decided talent.
He married Mary Morgan from Ballybay, County Monaghan, on 8 April 1967. They have three children, Siobhan, Fiacre and Eoin. The family moved into the country in 1976.
He admires the music of the Beatles and the skill of Louis Armstrong, likes American bluegrass fiddle music and has a deep respect for the artistry of Sean Maguire, the traditional Irish fiddler.
On Good Friday 1977 while in Australia John Sheahan celebrated his tenth wedding anniversary. Barney tried to persuade the teetotal John to drink a glass of champagne to mark the occasion. When John was reluctant to comply Barney urged, 'Ah come on John. After all it's not every year you celebrate a wedding anniversary'.
source: The Dubliners Scrapbook
Sometimes referred to as, "The quiet one," John is the only member of the group to have had a formal musical education. He was rather proud of this status Until quite recently when an old man in a rural district of Ireland came up to him, following a concert, and said, "Tell me, young fellow, do you read music or are you gifted?" John's introduction to music began at school with the Christian Brothers in Marino, Dublin, where he learned the tin whistle.
This experience was shared with Paddy Maloney, now of Chieftains' fame, and another classmate, Liam Rowsome, fiddle playing son of the legendary piper, Leo Rowsome. So you can see there was a certain musical pedigree in the making at that particular time. Soon he was to transfer the musical knowledge gained on the whistle to a fiddle he found lying around at home
Enthusiastically supported and encouraged by his parents, he attended the Municipal School of Music in Dublin where he studied classical violin for more than five years. During this time he continued to maintain his interest in Irish traditional music which sometimes led him to improvise on the "classics" by putting in a few embellishments here and there.
This, of course, was not approved by his tutor who would remark disparagingly, "Ah, ah, you're composing again!" However, he continued to apply his classical technique to his traditional playing which would ultimately lead to the development of that unique and much admired personal style so in evidence today.
Over the years, John has been in steady demand as a session musician on other artistes' records, the more recent being PADDY REILLY, FOSTER & ALLEN, DANIEL O'DONNELL, KATE BUSH, TERENCE TRENT D'ARBY and THE FUREYS.
Writing his own music has been one of John's hobbies for a number of years and recently led to a big chart hit with his composition, "The Marino Waltz." This tune was subsequently covered by a number of other artistes and was followed by the release of an album of original instrumental pieces which were co-written by renowned classical guitarist, Michael Howard, and entitled "In Our Own Time." Both are working together on a new album which should be released in 1992.
source: 30 Years A-Greying - sleeve notes