Scientific advisor to the Institute of Literary Studies of the Research Center for the Humanities. He studied Latin, Hungarian, and Ancient Greek at Eötvös Loránd University. Hajdu taught at the Department of Classical Philology of the University of Pécs, and as a visiting professor at Shanghai Jiao Tong University in China (2016-19); and is currently a visiting professor at Shenzhen University, School of Foreign Languages. He is the editor-in-chief of the journal Neohelicon and a member of the editorial boards of several journals of literary theory (Literatura, Frontiers of Narrative Studies, Proudy, Recherche Littéraire / Literary Research, Primerjalna književnost). In the field of narratology, he deals in particular with narratological approaches to ancient texts, and the interaction of plot threads, unity and collective narration.
His most important narratological studies include:
- The Rule of Description (special issue, ed.), Primerjalna književnost 42(2), 2019, 1-104.
- Of beginnings (ed.), Frontiers of Narrative Studies 6(1), 2020, 1-58.
- Az elbeszélésciklusok elmélete, Literatura 30, 2003, 163–184.
- The collective in the Hungarian narrative tradition and narrative studies, Neohelicon 45 : 2 (2018), 431-443.
- The rights of trees: on a Hungarian short story from 1900, Neohelicon 44 : 2 (2017), 389-401.