Neumann was born in Prachatice, Bohemia (modern-day Czech Republic. He attended school in Budweis and joined the seminary there in 1831. Two years later, he transferred to the University of Prague, where he studied theology. He intended to be ordained, but his bishop, in 1835, decided there would be no more ordinations, as Bohemia had a high number of priests already.
Neumann, who spoke eight languages then wrote to other bishops in Europe, but they all replied that they also had too many priests and could not ordain him. He was inspired by the missionary writings of Bishop Frederic Baraga in America, and because he had learned English by working in a factory with English-speaking workers, Neumann wrote to bishops in America, requesting to be ordained in the United States. In 1836, he arrived in the United States with very little money, and was ordained to the priesthood there. He was assigned by the Bishop of New York to work with recent German immigrants in mission churches in the Niagara Falls area, where he visited the sick, taught catechism, and trained teachers to take over when he left. After four years of service there, he realized his own need for support and came to understand the importance of communal activity in his work. He thus applied to the Redemptorists. He was accepted, and entered the novitiate of the order in Pittsburgh, Pennsylvania. In January, 1842, he took the vows to enter the order in Baltimore, Maryland. After six years of difficult but fruitful work with the order, he was appointed the order’s provincial superior in the United States. Neumann was naturalized as a citizen of the United States in Baltimore on February 10, 1848.
In March 1852, Neumann was consecrated in Baltimore, as Bishop of Philadelphia, Pennsylvania. He was the first to organize a Catholic diocesan school system and increased the number of Catholic schools in his diocese from one to two hundred. He also introduced the School Sisters of Notre Dame to the New World to assist in religious instruction and staffing the orphanage. In 1853, he established Saint Peter’s Parish in Riverside, New Jersey.
Neumann wrote in many Catholic newspaper and magazine articles. He also published two catechisms and a Bible history in German. There were also many teaching orders brought in by him.
In 1860, Neumann died in Philadelphia due to a stroke at the age of 48. On October 13, 1963, John Neumann became the first American bishop to be beatified. He was canonized in 1977 by Pope Paul VI. He is buried in St. Peter the Apostle Church in Philadelphia.