Josef Mayr-Nusser was born on 27 December 1910 in Bolzano into a rural German-Italian household.
He grew up on a farm in which his devout parents instilled in him Christian values along with his elder brother Jakob, who enrolled in a seminary to become a priest.

Mayr-Nusser became fascinated with the life and works of Frederic Ozanam and with the life of Saint Vincent de Paul.
To that end, in an attempt to emulate the pair and to help the poor in the spirit of charity, he joined the Society of Saint Vincent de Paul at the age of 22 and became its elected president in 1937.
Mayr-Nusser served as the president of the society in its Bolzano division and in that capacity constantly visited the poor, providing them both material and spiritual assistance, in the process becoming a vocal anti-poverty advocate.
In a 1938 letter to members, Mayr-Nusser said: "When a brother is going to visit a poor family, you should do everything to organize your time so you can spend at least 10–15 minutes to visit people".
In an attempt to deepen his understanding of faith, he studied the letters of St. Thomas More and the writings of St. Thomas Aquinas.

Mayr-Nusser's friends nicknamed him "Pepi" in his adolescence and early adulthood.
In 1934, he became the head of Catholic Action in the Diocese of Trent, accepting the invitation of Pope Pius XI to broaden his lay activities.
In addition to these posts that he filled, Mayr-Nusser secretly became a member of the anti-Nazi movement "Andreas Hofer Bund" in 1939.

On 26 May 1942 he married Hildegard Straub (1907–1998) and his son Alberto was born in 1943.

As part of Nazi conscription during World War II he was enrolled in the SS unit in 1944 which forced him to leave his wife and newborn son for training in Prussia; he was sent off on 7 September 1944.
Sometime during the war, his father was killed on the frontlines.
Franz Treibenreif (a comrade and friend) said of him on what became a fateful 4 October 1944: "Josef was pensive and worried.
Unexpectedly, he raised his hand: 'Sir Major-General', he said with a strong voice, 'I cannot take an oath to Hitler in the name of God.
I cannot do it because my faith and conscience do not allow it'".
Mayr-Nusser's friends attempted to convince him to recant or to cease from the explosive statement, but he eschewed their offers in order to stand up for his beliefs.
Mayr-Nusser believed ardently that National Socialism could not be reconciled in any way with the values of Christian ethics and believed that the ideology ran counter to the divine law of God.

As a result of this Mayr-Nusser was jailed and later transferred to Danzig where he was prosecuted.
While he was awaiting trial, Mayer-Nusser took to chopping wood and peeling potatoes, and was given the right to pray during his time in captivity.

From prison Mayr-Nusser sent a range of letters to his wife and said of his actions: "You would not be my wife if you expected something different from me".
In February 1945 he was sentenced to death for treason and was ordered to be shot by a firing squad at the Dachau concentration camp.
However he fell ill with dysentery, and en route via train to Dachau with approximately 40 others being sent to the camp, died on the morning of 24 February 1945.
When his corpse was discovered, he was found with a Bible and rosary on his person.

Mayr-Nusser's remains were transferred to the Church of San Giuseppe in Bolzano in 1958.
Josef Mayr-Nusser was born on 27 December 1910 in Bolzano into a rural German-Italian household. He grew up on a farm in which his devout parents instilled in him Christian values along with his elder brother Jakob, who enrolled in a seminary to become a priest.
Mayr-Nusser became fascinated with the life and works of Frederic Ozanam and with the life of Saint Vincent de Paul. To that end, in an attempt to emulate the pair and to help the poor in the spirit of charity, he joined the Society of Saint Vincent de Paul at the age of 22 and became its elected president in 1937. Mayr-Nusser served as the president of the society in its Bolzano division and in that capacity constantly visited the poor, providing them both material and spiritual assistance, in the process becoming a vocal anti-poverty advocate. In a 1938 letter to members, Mayr-Nusser said: "When a brother is going to visit a poor family, you should do everything to organize your time so you can spend at least 10–15 minutes to visit people". In an attempt to deepen his understanding of faith, he studied the letters of St. Thomas More and the writings of St. Thomas Aquinas.
Mayr-Nusser's friends nicknamed him "Pepi" in his adolescence and early adulthood. In 1934, he became the head of Catholic Action in the Diocese of Trent, accepting the invitation of Pope Pius XI to broaden his lay activities. In addition to these posts that he filled, Mayr-Nusser secretly became a member of the anti-Nazi movement "Andreas Hofer Bund" in 1939.
On 26 May 1942 he married Hildegard Straub (1907–1998) and his son Alberto was born in 1943.
As part of Nazi conscription during World War II he was enrolled in the SS unit in 1944 which forced him to leave his wife and newborn son for training in Prussia; he was sent off on 7 September 1944. Sometime during the war, his father was killed on the frontlines. Franz Treibenreif (a comrade and friend) said of him on what became a fateful 4 October 1944: "Josef was pensive and worried. Unexpectedly, he raised his hand: 'Sir Major-General', he said with a strong voice, 'I cannot take an oath to Hitler in the name of God. I cannot do it because my faith and conscience do not allow it'". Mayr-Nusser's friends attempted to convince him to recant or to cease from the explosive statement, but he eschewed their offers in order to stand up for his beliefs. Mayr-Nusser believed ardently that National Socialism could not be reconciled in any way with the values of Christian ethics and believed that the ideology ran counter to the divine law of God.
As a result of this Mayr-Nusser was jailed and later transferred to Danzig where he was prosecuted. While he was awaiting trial, Mayer-Nusser took to chopping wood and peeling potatoes, and was given the right to pray during his time in captivity.
From prison Mayr-Nusser sent a range of letters to his wife and said of his actions: "You would not be my wife if you expected something different from me". In February 1945 he was sentenced to death for treason and was ordered to be shot by a firing squad at the Dachau concentration camp. However he fell ill with dysentery, and en route via train to Dachau with approximately 40 others being sent to the camp, died on the morning of 24 February 1945. When his corpse was discovered, he was found with a Bible and rosary on his person.
Mayr-Nusser's remains were transferred to the Church of San Giuseppe in Bolzano in 1958.
Josef Mayr-Nusser