Dr. Steff has a Ph.D. in Security Studies and a Masters in International Studies (MInSt) from the University of Otago, Dunedin. After receiving his PhD, he spent two and a half years working for the New Zealand Ministry of Foreign Affairs in Trade, firstly in the International Security and Disarmament Division, where he worked on counter-terrorism and transnational crime issues, and then in the Strategic Policy Division, where he was responsible for developing strategic policy and providing support to NZ Inc agencies.

At the University of Waikato, he will teach courses on New Zealand Foreign Policy, International Relations, and International Security. He is the author of Strategic Thinking, Deterrence and the US Ballistic Missile Defense Project: From Truman to Obama (Routledge, 2014).

His most recent published work is Dr. Reuben Steff & Dr. Nicholas Khoo, Security at a Price: The International Politics of US Ballistic Missile Defense (Rowman & Littlefield, November 2017).

His research on nuclear deterrence, missile defense, and the security dilemma examines the nature of contemporary great power competition within a unipolar system. He is currently conducting research into New Zealand's place in the 'NZ-China-US triangle', the contemporary dynamics of nuclear deterrence and the implications of artificial intelligence for international security.