John Nepomucene Neumann was born on March 28, 1811, in the village of Prachatitz in Bohemia (now the Czech Republic). His father owned a small stocking mill and was also a minor village official, while his mother was a devout woman who attended Mass daily. Neumann did not have a strong inclination for the priesthood in his childhood, and at the age of twenty he was still unsure of his choice for a career. He finally made his decision with the help of his mother, who encouraged him to try theology. In 1831, he was accepted into the Budweis Theological Seminary, and from that point on, he never regretted his decision. Neumann spent two years at the diocesan seminary in Budweis, and then he transferred to the archdiocese at the University of Prague, where he completed his studies in 1835. He intended to be ordained there, but in 1835, his bishop decided there would be no more ordinations since they had a high number of priests already. His academic record was excellent, and he had exceptional skill in mastering languages. In addition to his native German and Bohemian languages, he knew Italian, Spanish, Greek, Latin, English, and French. Additionally, later in life he taught himself Gaelic in order to minister to Irish immigrants. Neumann wrote to other bishops in Europe, but they all replied that they also had too many priests. At the seminary, Neumann made up his mind to become a missionary in America. This was after he was inspired by the missionary writings of the American Bishop Frederic Baraga.

Neumann wrote to bishops in America, requesting to be ordained in the United States. He was welcomed to the Diocese of New York at the age of 25 by Bishop John DuBois, and he was ordained in June 1836. He was assigned to mission churches near Buffalo, New York, until he applied to the Redemptorists, members of the Congregation of the Most Holy Redeemer, a Roman Catholic order founded in 1732 by Saint Alphonsus Liguori. In January 1842, he took his vows in Baltimore, Maryland, and he became the first Redemptorist in the New World. Neumann's first assignment was to teach catechism in German to a group of children, who were soon receiving first Communion. He later traveled to Pittsburgh and became a Redemptorist lay brother, a mission he would serve for the rest of his life.

Neumann had many accomplishments throughout his life including administering to the largest diocese in the country and building new churches, one almost every month. He had a fond love for children; he was the first to organize a Catholic diocesan school system and increased the number of Catholic schools in his diocese from two to one hundred. He founded a new religious community, the Sisters of The Third Order of St. Francis of Philadelphia, and he saved the Oblate Sisters of Providence from dissolution. He had also established the pattern for parochial school systems in America by changing them into a diocesan system and originated the Forty Hours Devotion for year-round prayer. Most importantly, he was a priest of extraordinary spirituality, with intense devotion to the Eucharist and selfless commitment to the service of all people. Neumann never wanted any position of authority and begged not to be made a Bishop. However, in 1852, at the age of 41, he was declared a Bishop by Pope Pius IX. After his installation, because of his short stature, many called him, with great affection, "Our Little Bishop."

He soon developed a persistent and racking cough that took much of his strength. He knew that his end was near, yet he refused to give up his work. Neumann was the Bishop of Philadelphia for less than eight years before his sudden death on January 5, 1860, when he suddenly collapsed walking down Vine Street in Philadelphia. Neumann's burial was in the crypt of St. Peter the Apostle's Church in Philadelphia, and because the church was an active and popular site, special permission had to be granted for his burial here. Neumann performed many of his services here and was also a friend and an advisor to many of the poor German parishioners that belonged to the church. The Neumann shrine is still located there today; however, his body lies beneath the altar, the first of all American bishops ever to be raised to the altars of the Church.

In 1976, 116 years after his death, the Sacred Congregation for the Causes of Saints recommended to Pope Paul VI that Neumann be enrolled in the calendar of Saints of the Roman Catholic Church. The Pope signed the decree approving this proposal, and on December 20, 1976, his final word was given for Neumann's canonization. In proposing a candidate for beatification, the Church requires that two miracles be attested and proven. After beatification two more miracles must be approved before the candidate is canonized, or declared a Saint. In Neumann's case, the first miracle proven was that of Eva Benassi, an eleven-year-old girl living in the town of Sassuolo, Italy. She was diagnosed with acute diffused peritonitis, with death imminent. Eva woke one next morning, entirely cured after praying to Neumann for intercession. The second of Neumann's miracles occurred in Philadelphia in July 1949. James Kent Lenahan, a nineteen years old boy, was in an unusual automobile accident and was crushed between a car and a telephone pole. His injuries included a crushed skull, a pierced lung, a broken collarbone, and three broken ribs, as well as other internal complications. His injuries were so bad that doctors did not even intend to operate. After his parents placed Neumann's picture on top of James, he was soon released from the hospital, having made a complete recovery. Another young boy, Michael Flanigan, diagnosed with bone cancer, which was rapidly spreading to his lungs, had several unsuccessful operations, yet was soon to be fully recovered with no cancer ever to be found again. This miracle happened after his parents took Michael to the shrine of Bishop Neumann in Saint Peter's Church. Prayers were offered, and a relic was applied to the cancer. The symptoms then miraculously disappeared. After accepting this cure as an authentic miracle, Pope Paul VI did not need to find a fourth miracle to declare Bishop Neumann a saint.

A Franciscan college in the suburbs of Philadelphia, Our Lady of Angels College, located in Aston Township, Pennsylvania, was renamed as Neumann College after his beatification in honor of his memory. South Catholic High School, an all boys secondary school in Philadelphia, was renamed to honor Bishop John Neumann as well. St. Neumann Hall, a residence hall at LaSalle University, was built in 1989. The hall was named after Bishop Neumann because he drew many religious teaching orders to Philadelphia, including the Christian Brothers, a Roman Catholic religious teaching order, and because he organized the patriarchal school system in Philadelphia. His feast date is celebrated on the anniversary of his death, January 5th.