Johannes Katschthaler was born in Hippach, in the Austrian Tirol, and studied at the seminary in Salzburg.

He began teaching ecclesiastical history at University of Innsbruck in 1874, and became a canon of the cathedral chapter of Salzburg in 1880.

On 4 June 1891 Katschthaler was appointed Auxiliary Bishop of Salzburg and Titular Bishop of Cybistra by Pope Leo XIII, receiving his episcopal consecration on the following July 12 from Archbishop Johannes Evangelist Haller.

Leo XIII created him Cardinal Priest of San Tommaso in Parione in the consistory of 22 June 1903.

During his tenure, he participated in the papal conclave of 1903, which elected Pope Pius X, and promoted the Theological Faculty of Salzburg to form a separate University.