This brought him to the attention of the founder of the journal al-Machriq, Louis Cheikhô, for whom Graf held a high regard.
In 1918 Graf obtained a doctorate of theology from the University of Freiburg with a monograph on Marqus Ibn al-Qunbar (Ein Reformversuch innerhalb der Koptischen Kirche im zwölften Jahrhundert), published in 1923.
In 1930 he was named Honorary Professor for Christian Oriental literature at the theology faculty of the university of Munich.
Literary encyclopedia of Arab-Christian authors, with related biographic and bibliographic material, summary of their works, editions, translations and studies, and index to the manuscripts sources.
He was a long-term contributor to the Arabic series of the Corpus Scriptorum Christianorum Orientalium and the journal Oriens Christianus.