[citation needed] In addition to his duties as archbishop of Munich, on 11 December 2010 Marx was named by Pope Benedict as a member of the Congregation for Catholic Education for a five-year renewable term.

[10] On the question whether the Church should allow people who have divorced and attempted remarriage to partake in Holy Communion, it came to disagreements with Gerhard Ludwig Müller, the head of the Congregation of the Faith at the Vatican, in November 2013.

After Britain voted to leave the European Union in June 2016, Marx issued a statement saying: "This decision of the British voters should of course be respected, even if we, as COMECE, find it extremely regrettable.

"[30] When several cardinals who believed that no circumstances allow for someone who had attempted remarriage to receive communion published a set of questions asking for clarifications of Amoris Laetitia, Marx objected.

[46] In February 2018, it was widely reported that Marx said in an interview with German journalists that blessing of same-sex unions is possible in Catholic churches in Germany,[47][48] but later clarified that he had not implied this and was misunderstood, stating that there merely could be "spiritual encouragement.

[50] In February 2022, following a television documentary produced by a group called 'OutinChurch', in which 120 German priests, church employees and lay people identified themselves as LGBT, Cardinal Marx stated "Not everyone is obliged to declare [to others] their own sexual inclination, whether heterosexual or homosexual.

[52][53] On 13 March 2022, Cardinal Marx celebrated a mass marking '20 years of queer worship and pastoral care' at St Paul's parish church in Munich.

He called for a 'dynamic of openness', referring to the synodal path of the Catholic Church in Germany, and said that this was what Pope Francis meant when he spoke about the need to "discover what the Spirit has to say to us today.

[55] It was reported in August 2022, that Marx was going to award the Catholic Media Prize to the LGBT documentary "Wie Gott uns schuf – Coming-out in der Katholischen Kirche".

On the occasion of the 2015 pro-life march in Germany, he publicly stated: "As Christians we share the conviction that the inviolable dignity of every human being has its origin in God, the Creator of all life.

He said that in past times there were occasions when the church was on 'the wrong side' of various issues, but that in the future it must rely on its own social doctrine and Christian anthropology as a source from which to help make a new and better society, which also embraced the marginalized.

He also expressed concern over a tendency by some to want to go back to a dream of society where things were 'more cohesive and simpler', and that future debates would be about identity and security rather than freedom.

[69]On 5 September 2015, Marx along with Lutheran bishop Heinrich Bedford-Strohm, members of the clergy and crowds of Germans enthusiastically welcomed Syrian refugees coming to Germany at the Munich train station.

"[78] In July 2018, the Bavarian Christian Social Union (CSU) party nearly pushed Angela Merkel's government to the brink of collapse after it demanded that she do more to restrict the number of migrants entering Germany.

Representatives of each country's bishops signed a statement about their common mission to build a Europe based on Christianity and the need for continued efforts to recover from their past as wartime adversaries.

"[92] In July 2023, Marx met with a delegation from the Italian village of Filetto di Camarda and apologized on behalf of the diocese to them on account of the wartime atrocity committed there by Matthias Defregger, former auxiliary bishop of Munich.

[101] Following the publication of the report on sex abuse in the Munich archdiocese in early 2022, Cardinal Marx spoke out in favour of lifting celibacy rules for priests.

"[103] At the 'Synodal Path' meeting held in Frankfurt in September 2022, a proposed document calling for changes to church teaching on various subjects, including sex, gender and masturbation, failed to pass as a result of a lack of necessary votes.

[107] In a September 2022 interview with La Croix, Marx claimed that they had no intention of 'rewriting dogma' and that the proposals at the Synodal Path to allow for blessings for homosexual couples and remarried divorcees were a 'change of paradigm and perspective'.

He said, 'I implore the Patriarch of Moscow to exert his influence on the president so that the war stops and arms are laid down' and 'While we bishops are not politicians, it is our task and our duty to proclaim the Gospel’s message of peace – especially to those who are of the opinion that they can push their political aims on people with force and terror'.

"[122] In a Christmas Eve message in 2022, Cardinal Marx and Annette Kurschus, the head of the Evangelical Church in Germany, condemned war and violence while justifying Ukraine's right to defend itself against Russian aggression.

[123] In June 2023, Marx awarded the Catholic Fritz Gerlich Prize to the Danish film Unruly about a woman in 1933 consigned to an institution for disobeying social norms.

I believe we underestimate in our country what it means to have functioning institutions that can also deal with difficult situations,” [125] During the 2015 Synod on the family, Marx faced opposition from other bishops for supporting Kasper's proposal that the rules be relaxed to allow people who have divorced and attempted remarriage to receive Holy Communion.

[128] When Pope Benedict died on 31 December 2022, Cardinal Marx praised him and said "We mourn a faithful witness to God’s love and an important teacher of the Church, whose proclamation already shone far beyond the borders of the Archdiocese during his time as Archbishop of Munich.".

[138] American cardinal Raymond Leo Burke in a May 2022 interview claimed that the German bishops who were advocating changes to church teaching on homosexuality or women's ordination were supporting heresy.

"[142] In February 2019 Marx spoke at a conference on paedophilia in the Catholic church summoned by Pope Francis, saying that procedures to prosecute offenders "were deliberately not complied with", and files were destroyed, or not created, allowing abuse to continue.

Marx promised that the Archdiocese of Munich would publish its own report on sexual abuse once it was finished in 2021, which would name those who were responsible and that it would not be about sparing his predecessors (Joseph Ratzinger and Friedrich Wetter).

The Archdiocese of Munich stated that Pope Francis had allowed Marx to make his resignation letter public, and asked him to remain in his role until he had received an answer.

[155] In the aftermath of the report by the law firm, Marx said he would not attempt to make another resignation as he had done the previous year and said that: "I am ready to continue serving if that is helpful for the further steps that have to be taken for a more reliable reappraisal, even more attention to those affected and for reform of the church".

[158] In January 2023, on the one-year anniversary of the publication of the report on sexual abuse in the Munich archdiocese, Marx commented, "I will always be responsible for the suffering that this entails and I therefore apologize again...I can’t undo what happened, but I can act differently now and in the future.