Tomislav received his PhD in 2005 for the doctorate Utopias of Nation: Local Mass Killing in Bosnia and Herzegovina, 1941-44. In 2008, he became the Director of Research at the Programme for Holocaust and Genocide Studies, Uppsala University, and in 2013 the Director of the Hugo Valentin Centre. He currently works as a senior lecturer at the Centre, where he teaches several courses on a two-year Master Programme in Holocaust and Genocide Studies.
Dulić's dissertation project dealt with the microfoundations of violence in a number of municipalities in Bosnia and Herzegovina perpetrated mainly by Coatian and Bosniak fascist Ustašas and Serbian nationalist Četnik formations. His research focus has since developed from an original theoretical emphasis on sociology and social-psychology combined with macro/micro-relations, to an approach that seeks to combine these with theoretical models from the field of "civil wars studies". These issues have been explored in several articles, including one that deals with how the Yugoslav concept of a "General People's Defence", which drew upon the experience of partisan warfare during the Second World War and the Marxist notion of guerrilla warfare first formulated by Friedrich Engels, contributed to the war of the 1990s. A more recent article has dealt with counter-insurgency (COIN) warfare and clashes involving Yugoslav Partisans and Regiment Dänemark of the 11th Waffen-SS Panzergrenadier Division "Nordland" in Croatia during the Second World War.
Another important focus of his research concerns the relationship between mass violence and geographic space. In 2015, he published an article on the different motives of violence in the Independent State of Croatia, where he used statistics from a database that is under development and contains individual-level georeferenced information for 77,000 victims of the Jasenovac concentration camp in order to show how differences in motives also had a profound impact on the age and gender make-up of various victim groups (with the Roma group displaying an almost perfect population pyramid). In a forthcoming article, he uses the same dataset to analyse not only the socio-economic structure of different victim groups, but also to provide a spatial analysis of the Yugoslav camp system with a particular emphasis on the victimization of Jews.
Dulić's research interest also concerns memory culture and in particular how the memory of historical atrocity influences politics and post-conflict peace-building. He has written about the late Croatian president Franjo Tuđman's use of highly antisemitic sources in a book from 1989 that caused international condemnation; the efforts by communist Yugoslavia to create a unifying master narrative as part of the post-Second World War transition; as well as about the recently concluded process of legal rehabilitation of the Serbian Četnik leader Dragoljub Draža Mihailović.