Henrik Syse was Head of Corporate Governance for Norges Bank Investment Management (NBIM), which manages Europe's largest sovereign wealth fund, the Government Pension Fund of Norway Global, from 2005 to 2007, and he continued, until 2009, as an advisor and consultant on social issues for NBIM.

At PRIO, Henrik Syse specializes in the ethics and laws of armed conflict, as well as other issues within international ethics, and he also works on questions related to free speech, identity, values, and the aftermath of the 22 July 2011 Norway attacks.

Among his publications in English are The Ethics of War: Classic and Contemporary Readings (edited with Gregory Reichberg and Endre Begby, Blackwell, 2006), Natural Law, Religion, and Rights (St. Augustine's Press, 2007), and Religion, War, and Ethics: A Sourcebook of Textual Traditions (edited with Gregory Reichberg and Nicole Hartwell, Cambridge University Press, 2014).

He has published several books in Norwegian on issues such as faith and reason, free speech, and applied ethics.

He is an active Sunday School teacher in his local church at Fagerborg in Oslo, and is also a regular guest in Norwegian National Broadcasting (NRK), not only speaking about politics and philosophy, but also as a featured guest discussing The Beatles on the popular radio show Herreavdelingens platesjappe.