William MacMillan


William M. MacMillan is the Chief Information Security Officer (CISO) at the Central Intelligence Agency (CIA).  Prior to assuming his current role, William served in multiple senior leadership positions dealing with various aspects of intelligence, counterintelligence, and cyber operations.

As Chief of Digital Innovation in CIA’s Counterintelligence Mission Center (CIMC), he worked closely with CIA’s Chief Information Security Officer (CISO), Chief Information Officer (CIO), and other senior stakeholders on mitigation of enterprise risk.  During this time he focused significant attention on insider threat, supply chain risk, and incident response issues, as well as the development of CIA’s Cybersecurity Operations Center (CSOC).

William also held several key leadership positions in CIA’s Center for Cyber Intelligence (CCI), which is responsible for intelligence collection, analysis, and operations focused on foreign cyber threats to US interests.

Earlier in his career, he served in multiple overseas tours as an Operations Officer, employing specialized training and foreign language skills to conduct intelligence operations in support of US national security. He held several key leadership positions during this time, including Chief of Base in a war zone.

Prior to joining CIA, William served as an officer and a pilot in the United States Air Force (USAF). He held multiple leadership positions in the USAF’s Combat Rescue and Special Operations communities, where he developed and employed cultural expertise focused on the Middle East and Central Asia.

William graduated from the United States Air Force Academy with a BS in Biology. He has also obtained an MA in International Relations and an MS in Management of Secure Information Systems.

A lifelong student of leadership and organizational theory, William is dedicated to creating high-performing, innovative, inclusive organizations grounded in ethical leadership and the empowerment of individuals. He believes a happy, healthy workforce achieves more, and he is therefore passionate about infusing Wellness and Resilience resources into the workplace.

William and his wife – a STEM teacher in Northern Virginia public schools – are the proud parents of three amazing teenagers.