It made him particularly sensitive to the issue of bullying as he climbed the professional ladder to his present post as head of Bryn Celynnog comprehensive in Beddau, Pontypridd.
But now he is stepping down to campaign for his fellow heads and deputies, rather than pupils, as the new secretary of the Association of School and College Leaders in Wales.
He takes over from Brian Rowlands, who stands down on September 1 after seven years at the helm of what was the Secondary Heads Association Cymru.
"It took a very special opportunity to persuade me to leave Bryn earlier than expected," said Mr Jones, aged 56.
"The school has a wonderful ethos, it's like a family. There is a real sense of caring for each other among the students and staff, and a determination to achieve the best. I've always felt it's a privilege to be the head here.
"But the chance to take on this challenge is one that doesn't come along every day."
After many years' involvement with ASCL's executive in Wales and its UK council, Mr Jones believes he has come to his new job at a particularly exciting time.
"Succeeding Brian Rowlands presents new challenges for me, as devolution brings about an increasing difference between England and Wales on issues such as funding, curriculum and assessment, and evaluation," he said.
But he said his priorities would be determined by the members.
Mr Jones was born and raised in England, the youngest of six children. His parents, Welsh-speakers from Cardiganshire, had a dairy farm near Stoke Mandeville. It was on his first day at grammar school in Aylesbury that he was chased by a large group of fellow pupils chanting: "Taffy was a Welshman, Taffy was a thief."
After graduating in economics from Liverpool university, he was encouraged into teaching by his future wife Alison, who now teaches English in Newport.
Posts in Surrey and South Yorkshire were followed by a move to Deeside high school in Clwyd, in 1979, and a deputy headship at Lliswerry high in Newport, in 1985. He has been head of Bryn Celynnog since 1992.
Having established himself in Wales, he doesn't intend to leave - not even for the house he is restoring in France.
"It's the sense of community here that makes Wales a special place to live," he said.
His appointment was welcomed by John Dunford, general secretary of the ASCL.
"Gareth is ideally suited to carry on the excellent work of Mr Rowlands, who has so ably represented the views of secondary schools and college leaders in Wales for the past seven years," he said.