Paul Werth joined the University of Nevada, Las Vegas in 1997, after receiving his PhD at the University of Michigan in 1996, and is now Professor in the Department of History. He has been a fellow at the Slavic Research Center at the University of Hokkaido (Japan); at the National Humanities Center in North Carolina; the Center for Advanced Study at Ludwig-Maximilians University in Munich; the American Academy in Berlin; and the Swedish Collegium of Advanced Studies in Uppsala. In 2022 he was named a Fellow of the John Simon Guggenheim Memorial Foundation and earlier received support from the National Endowment for the Humanities. 

From 2010 to 2015 he was one of the three editors of the journal Kritika: Explorations in Russian and Eurasian History and has served on the journal's Editorial Council since then. In 2013-14 he was chair of UNLV's Faculty Senate, and after that chair of UNLV's Promotion & Tenure Committee and then chair of its Department of History (2015-17) and Undergraduate Coordinator in that department (2019-22). He currently serves as co-chair of UNLV’s Heterodox Academy Campus Community.

His research focused initially on religious freedom in the Russian Empire and the role of religious institutions and personnel in tsarist imperial governance. He has published articles in Social History, Slavic Review, Nationalities Papers, Kritika, Comparative Studies in Society and History, Russian Review, Ab Imperio, Cahiers du Monde russe, and Journal of Modern History. His first book, At the Margins of Orthodoxy, was published with Cornell in 2002, and a book of his essays in Russian translation appeared in 2012 as Православие, инославие, иноверие (NLO). In 2014 he completed The Tsar's Foreign Faiths: Toleration and the Fate of Religious Freedom in Imperial Russia (Oxford). Among his current projects in this area of research is Russia’s Other Eastern Church, an exploration of the place of the Armenian confession in tsarist Russia’s religious and geopolitical landscape (under contract with I. B. Tauris publishers).

Other projects have moved in different directions. In 2021 he published 1837: Russia's Quiet Revolution (Oxford), a book intended to reveal the dynamism and consequence of a neglected but critical moment in Russia’s history. He has since turned to questions of borders, territory, and sovereignty, and has completed How Russia Got Big: A Territorial History, which narrates seven centuries of Muscovite, imperial, Soviet, and post-Soviet Russian space (planned for release in the “Russian Shorts” series with Bloomsbury Publishers in 2025). A larger project, Russia’s Enclosure: A History of the Longest Border (contracted with Oxford University Press), explores Russia's boundaries from Norway to North America, and from the early modern period to the present.