Born in the village of Pszczyna (in the Opole region of Prussian-held Poland) September 12, 1843, Karol Lanz entered the Resurrectionist seminary in Rome, Italy in 1866. He furthered his studies at Kitchner's (Ontario, Canada) St. Jerome's College. Returning to Rome, he was ordained to the priesthood by Cardinal Patrizi on January 5, 1873.

After having arrived in the United States later that same year, Lanz worked at the Church of the Holy Trinity (a Resurrectionist parish) in Chicago. In 1875, he returned to Rome, asking to be released from his vows as a Resurrectionist priest. While in Europe, Lanz had the opportunity to visit his native land as well as other countries.

Later that year, he returned to the United States and came to the Diocese of Buffalo; there he was assigned to helping the Poles in Dunkirk, NY organize St. Hyacinth Parish. Lanz remained at the parish for almost four years before entering the Benedictine monastery in Latrobe, PA. In July 1880, he professed his vows as a Benedictine and was given the name Jacek (Hyacinth).

Ojciec Jacek was first assigned to the Polish parish of St. Stanislaus in Pittsburgh PA, then to St. Stanislaus Church in Erie, PA. Later records show him to have been an instructor at the seminary connected with the Latrobe monastery and as having died there November 15, 1892.