Mario Fischer has served as General Secretary of the Communion of Protestant Churches in Europe (CPCE) since 2018. From 2015 onward, he worked at the CPCE office in Vienna as Head of Office and coordinator of the 2017 Reformation Anniversary at the European level, before the CPCE Council appointed him as the first full-time General Secretary. He succeeded Bishop Michael Bünker in this role.

The 49-year-old theologian is originally from Darmstadt and studied theology, philosophy, and ecumenism in Mainz, Marburg, Rome, and Munich. In 2004, he completed his First Theological Examination with the Protestant Church in Hesse and Nassau. In 2012, he was awarded a doctorate at the University of Philosophy in Munich with a dissertation on the significance of religious experience in the phenomenology of early Heidegger. His doctoral supervisor was Gerd Haeffner.

Mario Fischer is an ordained minister of the Protestant Church in Hesse and Nassau (EKHN). He completed his two-year vicariate in 2008 and 2009 in Weilburg and Selters an der Lahn. He then served for one year as a special vicar at the CPCE office in Vienna. From 2011 to 2014, Fischer was pastor in Steinheim am Main (EKHN) and served as vacancy representative for several congregations in the Rodgau deanery. After completing his studies, he also volunteered as a firefighter and fire brigade chaplain.

Fischer is married and has two sons who were born in Vienna.

During his tenure as General Secretary, he succeeded in deepening church communion despite political polarization in Europe. Several Lutheran churches were admitted into the communion, and cooperation with Baptist and Anglican churches was intensified. CPCE was established as a public-law corporation in the Republic of Austria. Fischer registered CPCE as an international NGO with the Council of Europe and strengthened interchurch solidarity through aid projects. At the General Assemblies in Basel in 2018 and in Hermannstadt/Sibiu in 2024, he presented the member churches with strategic objectives for the coming years. His term also encompassed the COVID-19 pandemic, during which CPCE developed into a stronger ecclesial network for reflecting on contemporary issues at the European level, as well as the 50th anniversary of the Leuenberg Agreement, which was used across Europe to discuss the role of Protestant churches and the model of church communion.

Already at the 2024 General Assembly, Fischer announced that he would step down as General Secretary in 2026. As of 1 May 2026, he will assume his new position as Director of the Konfessionskundliches Institut in Bensheim.