Deissmann was professor of theology at the Ruprecht Karl University of Heidelberg (1897–1908), and then at the Friedrich Wilhelms University of Berlin (1908–1935). He was twice nominated for the Nobel Peace Prize, and held eight honorary doctorates from 6 different countries.^[2]

In 1904 he founded, together with Albrecht Dieterich, the Eranos circle in Heidelberg. Members included Ernst Troeltsch, Max Weber, Eberhard Gothein, Georg Jellinek, Karl Rathgen, and Wilhelm Windelband.^[3]

In Berlin, Deissmann's academic focus began to shift from Greek philology to the ecumenical movement, church reform and, significantly, international Völkerverständigung (i.e. peace-promoting mutual understanding between nations and cultures). From 1914 until 1922 he produced a regular semi-political international communiqué, the Evangelischer Wochenbrief (1914–1921), with its English equivalent Protestant Weekly Letters (1914–1917). Its target audience was primarily influential German and American Christians, and it provided a forum for the advancement of peace and understanding among nations.^[4]

In 1925 Deissmann became aware of the disintegration of ancient Ephesus, a historically important archaeological site, partly excavated before World War I under the auspices of the Austrian Archaeological Institute. Deissmann campaigned single-handedly for several years, both on a national and international level, to raise awareness of the plight of Ephesus, and managed to organise funding for the archaeological work to recommence in 1926, and continued annually until 1929.^[5]

Deissmann died on 5 April 1937, in Wünsdorf near Berlin, where he is buried in the local cemetery.

• Deissmann, Gustav Adolf (1892). Die neutestamentliche Formel "in Christo Jesu" untersucht (Habilitationsschrift).
• ——— (1895). Bibelstudien. Beiträge, zumeist aus den Papyri und Inschriften, zur Geschichte der Sprache, des Schrifttums und der Religion des hellenistischen Judentums und des Urchristentums. Marburg.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1897). Neue Bibelstudien. Sprachgeschichtliche Beiträge, zumeist aus den Papyri und Inschriften, zur Erklärung des Neuen Testaments. Marburg.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1901). Bible Studies: Contributions chiefly from papyri and inscriptions, to the history of language, the literature and the religion of Hellenistic Judaism and primitive Christianity. Translated by Grieve, A. Edinburgh.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1905). Veröffentlichungen aus der Heidelberger Papyrus-Sammlung. I, Die Septuaginta-Papyri und andere altchristliche Texte. Heidelberg.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1908). The philology of the Greek bible: its present and its future. Translated by Strachan, L.R.M. London.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1908). Licht vom Osten. Das Neue Testament und die neuentdeckten Texte der hellenistisch-römischen Welt. Tübingen.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1910). Light from the ancient East. The New Testament illustrated by recently discovered texts of the Graeco-Roman world. Translated by Strachan, L.R.M. London.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1911). Paulus. Eine kultur- und religionsgeschichtliche Skizze. Tubingen.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1914–21). Evangelischer Wochenbrief.
• ——— (1914–17). Protestant Weekly Letter.
• ——— (1923). The religion of Jesus and the faith of Paul. The Selly Oak Lectures, 1923 on the communion of Jesus with God & the communion of Paul with Christ. Translated by Wilson, W.E. London.{{cite book}}: CS1 maint: location missing publisher (link)
• ——— (1925). "Adolf Deissmann". In Stange, E. (ed.). Die Religionswissenschaft der Gegenwart in Selbstdarstellungen. Leipzig. pp. 42–78.{{cite book}}: CS1 maint: location missing publisher (link)

• Tiberius Julius Abdes Pantera

• A. Gerber, 'Protestantism and Social Liberalism in Imperial Germany: Gustav Adolf Deissmann (1866–1937) and Friedrich Naumann (1860–1919)', in Australian Journal of Politics and History, vol. 57, nr. 2, 2011, pp. 174–187.
• C. Markschies, ‘Adolf Deißmann – ein Heidelberger Pionier der Ökumene’, in Zeitschrift für neuere Theologiegeschichte, 12, 2005, pp. 47–88.
• C. Markschies, ‘Adolf Deißmann. Ein Pionier der Ökumene’, in C. Möller, et al., eds., Wegbereiter der Ökumene im 20. Jahrhundert, Göttingen, 2005, pp. 32–53.
• C. Nottmeier, ‘Ein unbekannter Brief Max Webers an Adolf Deißmann’, in Mitteilungen der Ernst-Troeltsch-Gesellschaft, vol. 13, Augsburg, 2000, pp. 99–131.
• C. Nottmeier, ‘Hermann Cohen und Adolf Deißmann: Dokumente aus dem Nachlaß Adolf Deißmanns’, in Zeitschrift für neuere Theologiegeschichte, 9, 2002, pp. 302–25.
• G. Harder / G/ Deissmann, Zum Gedenken an Adolf Deissmann. Vortrag anläßlich des 100. Geburtstages von Adolf Deissmann am 7. November 1966, gehalten am 26. April 1967 vor den Dozenten und Studenten der Kirchlichen Hochschule in Berlin, Bremen, 1967.

• Gustav Adolf Deissmann Protestant Weekly letter, 1914-1916 at Pitts Theology Library, Candler School of Theology
• Friedrich Wilhelm Bautz (1975). "Deißmann, Adolf". In Bautz, Friedrich Wilhelm (ed.). Biographisch-Bibliographisches Kirchenlexikon (BBKL) (in German). Vol. 1. Hamm: Bautz. cols. 1248–1249. ISBN 3-88309-013-1.
• On Deissmann's linguistic ideas by James Hope Moulton, 1914
• Schaff-Herzog article, Hellenistic Greek by Deissmann
• Newspaper clippings about Gustav Adolf Deissmann in the 20th Century Press Archives of the ZBW