 At the "Angelicum", he obtained a baccalaureate, a licentiate and a doctorate in philosophy by 1901 and a doctorate in theology in 1902.Grabmann studied palaeography at the Vatican Library and was encouraged by two of the most distinguished palaeographers of the time, Henry Denifle, the prefect of the Vatican library, and Cardinal Franz Ehrle

Grabmann was made a professor of theology and philosophy at the Catholic University of Eichstätt in 1906.The first of his great works, "Die Geschichte der scholastischen Methode", in two volumes, 1909 and 1911 made extensive use of unpublished medieval texts.