[1] While preparing to enter St. Patrick's College, the main Irish seminary in Maynooth, Quarter met a priest who had served as a missionary in the United States.

[2] At that point, Quarter decided to enter a seminary in the British Colony of Quebec with the goal of becoming a missionary.

[1] With permission from Bishop James Doyle of Kildare and Leighlin, Quarter sailed from from Ireland in April 1822, arriving in Quebec City.

[2] He then applied for admission to seminaries operated by the Archdiocese of Quebec and the Diocese of Montreal, but they rejected him because he was only 16 years old.

[3] In 1833, the diocese appointed Quarter as pastor of the new St. Mary's Parish on the Lower East Side of Manhattan.

[3] In 1840, Quarter began conversing with Maximilian Oertel, a former Lutheran minister from the Kingdom of Bavaria who had become disillusioned with his church.

[2] On November 28, 1843, Quarter was appointed the first bishop of the newly erected Diocese of Chicago by Pope Gregory XVI.

He received his episcopal consecration on March 10, 1844, from Bishop John Hughes, with Bishops Benedict Fenwick and Richard Whelan serving as co-consecrators, at St. Patrick's Cathedral in Manhattan[5] While still in New York City, Quarter met Mother Frances Ward, who was arriving with several religious sisters of the Sisters of Mercy from Ireland.

With the creation of a new diocese in Illinois, the bishop of Vincennes started recalling all his priests back to Indiana.

In February 1845, the Illinois General Assembly passed a bill that incorporated the bishop of Chicago, allowing him to "hold real and other property in trust for religious purposes.

The project ran into trouble later that year when the contractor was jailed for failing to pay a lumber bill.

That same year, they founded Saint Xavier College for women, the first Catholic institution of higher learning in Chicago.