Ordained a priest in 1843, McIntyre served in a number of parishes, including in Quebec and his native Prince Edward Island.
In the field of education, McIntyre established many churches and schools in the diocese, including a convent in the Magdalen Islands.
He was also responsible for erecting St. Patrick's School for Boys next to St. Dunstan's Basilica, and followed in the footsteps of his predecessor Bernard Donald McDonald by bringing Sisters of Notre Dame to teach on Prince Edward Island.
McIntyre was also instrumental in establishing the Catholic Total Abstinence Union which spread through the diocese during the 1870s to help prevent the danger of alcohol consumption.
His funeral was held at St. Dunstan's Basilica and his remains were taken by train to his native parish of St. Peter's Bay to be interred in the basement beneath the church altar.