Since September 2021, Mary Ellen Callahan has served as Chief of Staff to the Deputy Secretary of the Department of Homeland Security, John K. Tien. In this role, she provides substantive policy advice to the Deputy Secretary on a wide range of domestic and international policy issues and manages the day-to-day operations of the office. Ms. Callahan previously served in the Department as the Chief Privacy Officer and Chief FOIA Officer under Secretary Janet Napolitano from March 2009 until August 2012.
In addition to her federal experience, Mary Ellen served as Assistant General Counsel for Privacy and Cybersecurity at The Walt Disney Company from 2017 – 2021. She was partner at two major international law firms; serving as the Founder and Chair of Jenner & Block’s Privacy and Information Governance Practice from 2012 – 2017, and Co-Chair of the Privacy Working Group at Hogan & Hartson (now HoganLovells) from 2005 – 2009.
Mary Ellen’s extensive experience has given her unique insight into the interface of privacy, civil rights, and civil liberties with cybersecurity and national security issues. She is a nationally recognized privacy attorney as well as a prolific writer and speaker on cutting-edge privacy issues.
Ms. Callahan is a graduate of the University of Pittsburgh, where she was on the Board of Trustees from 2009-2022, and The University of Chicago Law School.