The Catholic story in the colony of Western Australia (founded in 1829) began to take shape in 1841 when layman Robert D'Arcy, a school teacher, on behalf of a handful of Catholics asked Church authorities in Sydney to send them a priest. Rome too had been studying how to serve the distant colony with only 100 estimated Catholics in the Perth aerate result was the arrival at Fremantle, late in 1843, of Fr John Brady (later first Bishop of Perth) and a Belgian priest, Fr John Joostens, and a Catechist, Patrick O'Reilly. Curiously, Brady stayed only two months before setting off to Europe, but in that time he had been granted land on Victoria Avenue and commenced the building of the small church that became the colony's first Catholic cathedral, St John's, and which still stands today. Joostens stayed on and conducted a school in the building.

However, Church authorities in Rome had been led to believe there were 3000 Catholics and two million Aborigines in the colony. So three years later Brady returned as bishop, accompanied by 24 missionaries. Alighting at Fremantle in January 1846 were Benedictines, Sisters of Mercy, Heart of Mary priests and brothers, diocesan priests, catechists and laymen. They were from Spain, Ireland, Italy, France and England.

The Mercy Sisters immediately set to providing Catholic education. The Benedictines promptly set off for New Norcia to work with Aborigines. However, a similar Heart of Mary mission to Aborigines near Albany failed. The 1851 arrival of St Joseph of the Apparition Sisters added to Catholic education efforts in Fremantle.

Increasing Benedictine numbers and a new monastery at Subiaco, now Wembley, enabled beginnings to be made of the present cathedral presbytery (1855) and the present cathedral (1863).

In 1859 New Norcia mission was separated from Perth and in 1867 became a separate jurisdiction which in 1903 expanded to reach from the coast to Southern Cross. That territory, which had grown to seven wheat belt parishes, reverted to Perth Archdiocese in 1973.

By 1854 Catholics expanded to 18 percent of the population due to free settlers, a number of Irish among the convicts, and young Irish women sponsored by the government.

The gold discoveries of the 1890s changed the face of Western Australia and of the Catholic Church by bringing an influx of lay Catholics from the eastern states of Australia, and prompting the bishop to seek more Religious orders to serve them.

In 1897 Geraldton was declared a separate diocese, its first bishop, William Kelly, being a native of York. Presentation and Dominican Sisters opened many schools in the northern Goldfields.

The Kimberleys, already a mission for 10 years, became a separate administration under the Pallottines in 1901. It became the Diocese of Broome in 1966.

In the south, Bishop Gibney brought in orders such as the St John of God Sisters, Christian Brothers, Oblates, Our Lady of the Mission Sisters, Loreto Sisters, and Good Shepherd Sisters, while Mary MacKillop's Australian Josephites expanded.

In the 1920s and 1930s the hitherto strongly Irish face of the Church began to change as Italian and Yugoslav migration picked up.

Big waves of migration after World War II meant the rapid expansion of parishes and schools, especially in country areas. St Charles' Seminary opened in 1942 to help provide additional priests to those still coming from Ireland in large numbers, with a sprinkling from Italy, Poland and Malta. Since 1949 there have been 150 ordinations from the Guildford seminary.

By 1954 it was time to create the separate diocese of Bunbury under Bishop Launcelot Goody. In 1980 the parishes of Mandurah and Pinjarra were added to that territory.

Among significant Perth developments in recent decades have been: the development of WA Catholic Education Commission and its Leederville administration; the restructuring of St Charles' as a complete local seminary; the establishment of Redemptoris Mater Neo-Catechumenate seminary; and the founding of the independent Catholic University of Notre Dame Australia.

According to the 2001 Commonwealth Census, there are 363,996 Catholics in the Archdiocese of Perth, 25.6% of the civilian population. 26.4% of the Catholics are under 18 years of age. They are served by approximately 150 diocesan priests, around 110 Religious priests, and nearly 600 Religious Sisters and 80 Religious brothers in 22 female and 23 male Religious congregations engaged in the wide range of apostolates. These work alongside the countless lay people in paid and voluntary positions in the agencies, organisations and 85 metropolitan and 15 country parishes of the Church in Perth.