His research and teaching focuses on genocides and wars in modern European history, especially on Holocaust perpetrators and bystanders; he also engages in the studies of both masculinity and body aesthetics.
He initiated and convened in 2009 and 2012 the first two events of the series International Graduate Conferences on Holocaust and Genocide Studies, a forum for doctoral students around the world.
In his research, Kühne has covered three fields: political culture of Imperial Germany; male bonding and mass violence in the twentieth-century; and body aesthetics in global history.
Thomas Kühne's early work inquired into the political culture of Prussia, the hegemonic federal state of Imperial Germany (1867-1918).
His dissertation, published in 1994 as Dreiklassenwahlrecht und Wahlkultur in Preussen 1867-1914 [Three-Class Voting System and Electoral Culture in Prussia, 1867-1914] and praised as a milestone in party and election history, elucidates why the Prussian three-class electoral law in Wilhelmine Germany, which even in its time was condemned as socially unjust, could survive for half a century, despite all signs pointing to mass politicization.