Primarily a historian of the Muslim communities of South Asia (India, Pakistan) from the eighteenth to the early twentieth centuries, Professor Green also specializes in the wider 'Persianate' world, including Afghanistan, Iran, and the Indian Ocean region. By training a historian of religion, he has worked extensively on the history of Sufism and other traditional modes of Islamic learning and organization. His work has ranged from the forms of Islam which evolved among the tribal societies of early modern Afghans to the intersection of religion and colonial service among the Muslim soldiers of the British Empire. His more recent work has expanded into nineteenth century intellectual interchange between Asia and Europe, Muslim travelers in Britain, Indian Ocean studies, and the history of the 'Islamic' book.
With a strong interest in Islam in the Middle East, Africa and Europe, Professor Green also works as a historian of Muslim societies more generally. Given the fact that South Asia is home to the world's largest Muslim population, his work seeks to position the region within a global and comparative perspective. To this end, Professor Green serves as chair of the UCLA Central Asia Initiative and on the editorial board of the International Journal of Middle East Studies.