The study offers the profile of life and work of M.J. Metzger, priest and martyr at the time of National Socialism in Germany and it presents his personal involvement in the pacifistic movement and in its national and transnational structures. Based on his articles and lectures the article is able to see his tangible encouraging approach and perspective of his theology of peace. Its fundamental elements are constituted by: international reconciliation as a principle of international peace; the foundation of peace is truth, justice, love; upholding of human rights; implementation of Christian politics regarding the overcoming of any nationalism; future federation of European states; peace as a category of the kingdom of God; shared responsibility of all Christians in social and moral questions; the criticism of failure to respond according to the spirit of Gospel; refusing of war and arm race; the peace as a problem of education. The second part of the study is concerned with the enforcement of his attitudes at the time of National Socialism and in consequence his persecution as ideological archenemy of regime, his imprisonment and execution. In the end we offer the ecclesiological and theological valuation of personage, in the last analysis as a significant figure and relevant theologian of the first half of the twentieth century, credited with rebuilding the Church, first of all on the field of ecumenism and practical life of faith of people moving toward a vision of the Church of The Second Vatican Council.