Father Walsh served as pastor at Brock. In April 1857 he was made parish priest of St Mary’s in Toronto, a parish established by Irish immigrants in 1852. A year later, he went to St. Paul's. In 1860, Walsh was made rector of the Cathedral, but chose to resign the position in 1861 and resume his former place at St. Mary's, while from April 1862 he also served as Vicar General of the Archdiocese.[1] In 1864, he was sent to Rome on business, toured Europe, and spent some time in Ireland.
He was consecrated as Bishop of Sandwich, Ontario in November 1867, and two years later returned the seat of the See to its previous site of London, Ontario and procured from Rome a decree making London once more the name of the diocese.[2] He served as Bishop of London, Ontario until 1889, when he was translated to the see of Toronto. Having paid off the diocese's considerable debt, Walsh the undertook the construction of St. Peter's Cathedral, designed by Joseph Connolly[3]
In August 1889 Bishop Walsh was appointed Archbishop of Toronto, and installed on 27 Nov 1889. During his tenure he established the Sacred Heart Orphanage at Sunnyside, and St. John's Industrial School for Boys,[4] and purchased land for the establishment of Mount Hope Catholic Cemetery, as St. Michael's was near capacity.[5] Walsh also invited French Canadian clergy from Quebec to staff the French-speaking parishes in Kent and Essex counties.
In 1894, the Archbishop secured a $40,000 (the equivalent of $1.48 million in 2024) gift from Catholic railway magnate Hugh Ryan to build a three-storey surgical wing for St Michael's Hospital, Toronto.[6][7] The expansion put the hospital on the path to becoming one of Canada's preeminent teaching University, with its state-of-the-art operating theatre designed to accommodate fifty medical students.[6]
