William Westerman is a lecturer in history at UNSW Canberra, co-author of the Official History of Australian Peacekeeping Operations in Timor-Leste, 2000-2012 and author of the Official History of Australian Operations in Iraq, 2003-2011. His research expertise includes Australian military history, First World War studies and contemporary warfare.

William earned a PhD from UNSW Canberra. He has held a number of academic and research positions, including as an ANU Teaching Fellow at the Australian Command and Staff College, Canberra, and as a researcher on the Official History of Australian Operations in Afghanistan, Iraq and East Timor at the Australian War Memorial. He is also a Fellow of the Royal Historical Society.

He is the author of several books on the First World War, including Soldiers and Gentlemen: Australian Battalion Commanders in the Great War, 1914-1918 (Cambridge University Press, 2017). He is also the author of several non-military history books, namely a short biography of former Victorian Premier Lindsay Thompson and a history of the 1996 merger of the Fitzroy Lions in the Australian Football League.