Patrick Joseph Harnett was born in Dublin on 22 May 1929, the third of seven children of Eileen and Michael Harnett. As a boy, he attended St Bridget's convent school, before proceeding to St Mary's College, Dublin. While at school, Patrick Harnett served daily Mass for the Capuchin Franciscan Fathers and hoped one day to join them. However, a chance meeting with a young seminarian, who was a member of the Sacred Heart Fathers, led to a change of direction.
Aged 15, he went first to the Sacred Heart Fathers' seminary in Earl Shilton, Leicestershire, and later to St Joseph's College, Malpas, making his Religious profession in 1949 at the age of 21. He was ordained priest on 8 December 1954.
Father Pat's first appointment was to teach history and Latin at the Sacred Heart Fathers' seminary Woodcote Hall in Shropshire. Then, in October 1961, he took up residence in St Patrick's presbytery in Liverpool and, at Archbishop Heenan's invitation, began what was to become the Archdiocesan Youth Service based in Evesham House in Aigburth. Father Pat's youth service ministry would span 28 years.
A new type of work awaited him when, in September 1989, he was asked to establish a Christian presence in the Albert Dock. On behalf of the Merseyside Christian churches, he set up the Riverside Ecumenical Chaplaincy. At the same time, he was appointed chaplain to St Mary's College, Crosby. Further chaplaincy work followed when, in January 1992, he was appointed Port chaplain and director of the Apostleship of the Sea, Liverpool.
Additionally, in December 1997, he became the parish priest of St Robert Bellarmine, Bootle. This was Father Pat's first and only appointment as a parish priest.
In May 2011 he underwent major surgery before going to Ince Blundell Hall for recuperation. It gradually became evident that his days as parish priest were over. He accepted "the Lord's will" with great trust, telling one of his visitors, "He knows what he is doing."
On 6 August 2016 Father Pat went to live in Stanley House, a dementia care home in Toxteth, in the area where his Liverpool ministry had begun some 55 years earlier. He died there peacefully on 17 July 2017.
His funeral Mass was celebrated by Bishop Vincent Malone at St Robert Bellarmine, Bootle prior to burial at Malpas.