Dr. Heinrich Hahn was born on August 29, 1800, in Aachen to a family that was particularly sensitive to religion, which instilled in him the practice of praying the daily rosary, a habit that he kept up with until his death on March 11, 1882, in the same town where he was born.

He became a doctor in 1822 at the end of a difficult academic path that led him to resist his uncle's pressure to study materials technology, for he preferred to study at the Faculty of Medicine in Ghent. It took him two years to obtain the qualification and title recognition, for which he was forced to move to Berlin to perform the obligatory military service as a voluntary surgeon for one year and then pass the ministerial examination after he returned to his hometown. In 1829, Hahn was happily married to Maria Barbara Odilia Känzler and blessed with the birth of ten children. Although he was devastated by the death of four of them and the premature death of his wife in 1866, Dr. Hahn worked hard and overcame these events in the light of the great faith that enlivened him. He was not just any doctor; Dr. Hahn always had an open door for the poorest patients, whom he often treated free of charge especially during births and epidemics, which was his answer to the indirect and unwanted criticisms that later reached him about the fact that generosity begins first and foremost at home. In addition to this charitable commitment, Hahn conducted interesting scientific analyses because he published a study on tuberculosis meningitis, which at the time seemed incurable, especially for children. It wasn't until he was 32 years old that something really important happened for Heinrich's vocation: the young doctor found a booklet on a patient's bedside table, called the Yearbook of the Society for the Propagation of the Faith in Lyon, in which he learned about the missionary work of Pauline Marie Jaricot. Hahn was intrigued and later decided to introduce the French model in Germany with the aim of generating enthusiasm for the missions and making the missionary commitment consistent and permanent. 

The first years of this commitment soon proved to be difficult for him. The model was French, and the political tensions that existed at the time were such that its implementation was resisted in Germany and Hahn's commitment to the universal Church met with little understanding in his own country.

Hahn did everything he could as a citizen and politician to create a more just and orderly society, which he considered God's will for humanity. For about forty years, he was a consultant and council member in his hometown where he committed himself to preventative health care and education for the lowest classes, while being for three years a member of the Berlin Parliament, demanding justice for all. As a man of faith, he was actively involved in many Catholic associations and brotherhoods, working towards a common vision in the Catholic sphere. He used to say to his critics, "we must accept that Christians have a father, God, and a mother, the Catholic Church, to which we all belong." Despite the resistance he faced, Hahn remained faithful to his universal vision with the strong support of prayer: "Those who pray for their neighbors are also willing to act on their behalf." He was right in the end because the awareness of missionary work grew. Dr. Hahn's unwavering conviction that the mission is a task for all Christians throughout the world led him to found the Missionary Association of St. Francis Xavier in Germany, a secular movement that still lives today in the Mission of the International Missionary Society. He continued his work late in life, offering to the Lord his suffering from an illness that led to his death.  On December 17, 2015 the Holy Father authorized the Congregation for the Causes of Saints to promulgate decrees concerning the heroic virtues of the Servant of God, Heinrich Hahn.