Michael Domenec was born on December 27, 1816, and baptized the same day at the parish church of Saint Peter in Reus, near Tarragona, Spain.

The outbreak of the Carlist War interrupted Domenec's studies; when he was age fifteen, his family fled Spain for political reasons.

They moved to France, where Domenec studied at the College of Montolieu in Aude, where he joined the Congregation of the Mission, also known as the Vincentians or Lazarites.

At Timon's invitation, Domenec joined the American mission, arriving at St. Mary's of the Barrens, a seminary in Perryville, Missouri.

[1] However, even though Domenec was opposed to debt, he was unable to deal successfully with financial involvements—the panic of 1873 was a fiscal disaster for the Pittsburgh diocese.

In the period after the American Civil War, when debts should have been paid off instead of more incurred, improvements upon the cathedral and the building of churches, convents, and schools had rolled up heavy obligations which the diocese could no longer meet.