The formal submission of the documentation from the diocesan phase to the Dicastery for the Causes of Saints in Rome has taken place.
This marks the beginning of the Roman phase of the cause.
Born in Dalkey, Co Dublin, in 1873, Willie Doyle entered the Jesuits in Rahan, Co Offaly, in the Diocese of Meath at the age of 18.
The Dubliner was renowned for his courage under fire, repeatedly running into No Man's Land to carry wounded troops to safety or to comfort those fatally injured.
A special ceremony was held in the Cathedral of Christ the King in Mullingar last month to mark the closing session of the Diocesan inquiry.
The Bishop of Meath, Most Rev Dr Tom Deenihan said that he is confident that the Cause will progress further.
He encouraged people to pray through the intercession of Fr Willie Doyle.
"Fr Doyle's generosity and heroism, which stemmed from his religious conviction, is an example for our time.
"It was very evident from the closing ceremony in Mullingar on 18 October that devotion to Fr Doyle has extended beyond his own century and is as relevant today as it ever was."
The documentation and evidence have now been formally submitted to the Dicastery for the Causes of the Saints in Rome who will scrutinise the evidence.
Fr Pascual Cebollada SJ, Postulator General of the Society of Jesus, will assume the role of Postulator for the cause, while Fr John Hogan of the Diocese of Meath will serve as Vice-Postulator.
"More than 3,000 pages of Fr Willie's writings, together with extensive historical and theological analyses and commentaries, have been assembled during the diocesan phase and were delivered to the Dicastery this week," said Fr John Hogan.
"This represents a major milestone in the cause for his canonisation.
"We will now begin work on the positio - the detailed study of Fr Willie's life, heroic virtues and reputation for holiness.
"Alongside this, we will continue to promote devotion to Fr Willie and encourage people to seek his intercession, particularly through prayer for miracles.
"We believe that Fr Willie's life and death have immense significance for the Church and for the world today.
"He is an inspiring model of priestly life and a sign of hope for those experiencing mental health difficulties, given his own experience of, and recovery from, a psychological breakdown in his youth."
President of the Father Willie Doyle Association Patrick Kenny said Fr Willie's cause for canonisation "has been greeted with remarkable enthusiasm, both in Ireland and internationally".
"Since the process began, we have received requests for information and materials about Fr Willie from people and organisations across Ireland and from countries throughout Europe, North and South America, and even Asia.
"Particularly striking has been the response of young people, who are drawn to the witness of his heroic life, his courage and his spirituality.
"The opening of the Roman phase is an important milestone, but there is still a considerable journey ahead.
"The work of promoting Fr Willie's life and spirituality must now intensify.
"Through public events, talks, publications and our growing international network, the Father Willie Doyle Association will continue to introduce new generations to his remarkable story."
What happens next?
The canonisation process can take many years.
During the Roman phase, the documentation will undergo detailed examination, including historical and theological assessment.
If the Church recognises that Fr Doyle lived a life of heroic virtue, he may be declared Venerable.
Beatification and canonisation are subsequent stages, ordinarily involving the recognition of miracles attributed to his intercession.
This was the first Irish cause to close in over forty years, the last being that of Venerable Nano Nagle, foundress of the Presentation Sisters.