At the direction of Cardinal August Hlond, he co-founded an order dedicated to serving Polish migrants, the Society of Christ.

[3][4] During World War II, he was appointed spiritual leader of Polish slave laborers in Nazi Germany with the permission of Pope Pius XII, Adam Sapieha, the archbishop of Kraków and the leader of the Catholic Church in occupied Poland and the Home Army.

In 1905, when, at his primary school in Szadłowice, religion was taught in German instead of Polish, Ignacy started a strike together with all the children.

Posadzy also became a co-editor of "Biblioteka Kaznodziejska" (The Preacher's Library) and "Wiadomości dla Duchowieństwa" (News for the Clergy).

In 1929, sent by Venerable August Cardinal Hlond, he traveled to Brazil, Uruguay and Argentina to gather information regarding the Polish communities there.

In 1930, again at the request of Venerable August Cardinal Hlond, Posadzy made another journey across the Atlantic to once again visit the Polish migrant communities in Brazil, Argentina, and Uruguay.

In 1938, Posadzy published a memoir of his travels to the Polish Communities of South America titled "The Way of the Pilgrims" (Drogą Pielgrzymów).

[6][2] In 1932, Venerable August Cardinal Hlond entrusted Posadzy with the establishment of a new religious order, the Society of Christ.

[7][2] Venerable August Cardinal Hlond had considered entrusting the spiritual care of the Polish diaspora ministry to a religious congregation for some time.

[7][2] In response to the Cardinal's request that he lead this new religious order, Posadzy initially replied that his health was poor and that he lacked the organizational skills for such an undertaking.

In Poznań, he gave a lecture at the "Słońce" cinema, which had the largest auditorium in the capital of Greater Poland.

Then Posadzy went to Italy to learn about the Scalabrinian order founded by Blessed Bishop Giovanni Scalabrini for the pastoral care of the Italian migrants.

After returning to Poland, Posadzy continued to promote the new order by giving lectures and writing articles for the press.

[2][7] On August 22, 1932, Cardinal Hlond gave his blessing for Posadzy begin the work of organizing the new order in earnest.

Along with this blessing, the Cardinal gave Posadzy final instructions and a few fatherly words of encouragement saying: So we begin In Nomine Domini.

The next day, August 23, Posadzy traveled to Potulice, where Countess Aniela Potulicka had donated her mansion and surrounding grounds to serve as the mother house of the new order, the Society of Christ.

[7] The Society began issuing the following magazines: "Głos Seminarium Zagranicznego" (Voice of the International Seminary), "Msza Święta" (Holy Mass), "Cześć Świętych Polskich" (Veneration of Polish Saints).

On his way back, he visited London, where religious brothers had been working for a year in the Polish Catholic Mission.

[2][7] When in September 1939 World War II broke out, the Society of Christ already had 20 priests, 86 seminarians and about 200 brothers and postulants.

In 1942, the priests of the Society of Christ managed to obtain a permit from the German authorities in Kraków for pastoral work in the so-called dulagach - transit camps for Poles deported to the Reich for forced labor.

[2] Posadzy relaunched the Society's publishing house and restarted issuing the monthly magazine "Msza Święta" (Holy Mass) after the wartime disruption.

[2]Posadzy, like most Catholic leaders in Communist Poland, had to navigate an extremely hostile, and often dangerous, political climate.

Posadzy refused to be associated in any way with the Polish communist party and the anti-Catholic campaign they regularly waged against the Catholic Church.

[2][3]The work of Posadzy's life, the Society of Christ, came of age in 1950 when it was recognized in the Church and received its "decretum laudis" (decree of praise) from the Holy See.

[1][2] In 1958, following a suggestion Venerable August Cardinal Hlond once gave him, he founded another religious order, the Missionary Sisters of Christ the King.

[2] In 1971, during Posadzy's golden jubilee of priesthood, Blessed Stefan Cardinal Wyszyński celebrated a Holy Mass in the Poznań cathedral.

[13][14][15] On June 16, 1999, in a letter to the Archbishop of Poznań, the Superior General of the Society of Christ, Tadeusz Winnicki SChr, formally requested that a cause for the beatification of Posadzy be opened.

On January 17, 2001, a ceremony at the Poznań Cathedral marked the beginning of the beatification process on the diocesan level during which evidence of Posadzy's heroic virtue would be gathered.

After reviewing the report, the Congregation issued a decree validating the diocesan investigation and granting Posadzy the title of Servant of God.

On June 21, 2018, the Positio super vita, virtutibus et fama sanctitatis was submitted to the Congregation for review.