Siegfried S. Hecker is a professor (research) in the Department of Management Science and Engineering, a senior fellow at FSI, and co-director of CISAC. He is also an emeritus director of Los Alamos National Laboratory.

Hecker's research interests include plutonium science, nuclear weapon policy and international security, nuclear security (including nonproliferation and counter terrorism), and cooperative nuclear threat reduction. Over the past 18 years, he has fostered cooperation with the Russian nuclear laboratories to secure and safeguard the vast stockpile of ex-Soviet fissile materials.

His current interests include the challenges of nuclear India, Pakistan, North Korea, and the nuclear aspirations of Iran. Hecker works closely with the Russian Academy of Sciences and is actively involved with the U.S. National Academies, serving as a member of the National Academies Committee on International Security and Arms Control Nonproliferation Panel.