Antoni Lex was born March 4, 1854 in Zulkowice, a rural village in the Slask region of Prussian-held Poland. Young Antoni studied in Glupczyce and Opole before serving in the Prussian military (where he advanced to the rank of an officer). Upon completion of his military duty, which played a significant role in his life, he enrolled at the Jesuit college in Innsbruck, Austria; it was here that he met the future bishop of Green Bay, WI Sebastian Messmer. Lex subsequently went on to Munich where, on March 14, 1883, he was ordained a priest for the Diocese of Green Bay by Archbishop Stischele.

That same year, he sailed for the United States; his first responsibility here was that of organizing the Church of the Sacred Heart in Marinette, WI. A year later, he was instrumental in organizing yet another Polish parish dedicated to Our Lady of the Scapular in Fancher.

After his tenure in Fancher, Lex spent the next four years serving as pastor of Sts. Peter and Paul Parish in Stevens Point, WI. While there, he built a brick church and a parish school (the first Polish school in the state not located in Milwaukee) and petitioned the Sisters of Notre Dame to staff the latter.

In 1889, Lex relocated to Detroit, MI where he served as the first pastor of St. Josaphat Parish. He remained there only a short time before switching pastorates with Ks. Mozejewski of St. Adalbert Parish in Buffalo, NY. His two-year stay at the parish was trying but fruitful; it was under his direction that the present church was completed and dedicated in 1891. By July 1892, Lex was reassigned to St. Hyacinth Parish in Dunkirk, NY where he is remembered for having built the parish school which served the community for 70 years. While at St. Hyacinth’s, he was visited by an old friend, Ks. Waclaw Kruszka. With Kruszka's encouragement, Lex eventually departed for Rome to continue his studies and earn a doctorate in canon law.

1901 saw Lex returning to the United States and again working in the state of Wisconsin. He was assigned to pastorates at St. Stanislaus, St. Casimir, and St. Vincent Parishes, all in Milwaukee.

In 1913, he became chaplain of Milwaukee’s St. Joseph’s Orphanage (operated by the Felician Sisters). He remained at this post until his death on December 5, 1935; his funeral was held at the Basillica of St. Josaphat in Milwaukee. In their comments, Ks. Lex’s charges portrayed him as a very gentle, kind and sharing person.