Jonathan L. Ullyot, known professionally as John Ullyot, is a former national security aide and communications strategist born on December 14, 1968, in Massachusetts, United States. He is the son of heart surgeon Daniel Ullyot and physician/author Joan Ullyot (born July 1, 1940, in Chicago, Illinois; died June 19, year unspecified; parents divorced 1976), and brother to Theodore Warren 'Ted' Ullyot (lawyer and venture capitalist). He graduated from Harvard College with an A.B. in Government-International Relations (1987-1991) and holds a certificate from the Pushkin State Russian Language Institute in Moscow. Ullyot served in the U.S. Marine Corps from 1991 to 1995 as an intelligence officer and scout sniper platoon commander, stationed on the U.S.-Mexico border with Joint Task Force Six and as liaison officer to the French Foreign Legion for jungle warfare training in South America. Fluent in French, German, and Russian at a business level, he resides in Washington, DC, and provides commentary on national security and political issues for outlets like Fox News, Newsmax, and NewsNation. He is a registered lobbyist with records on OpenSecrets and LegiStorm, including funded travel disclosures, and maintains a professional profile on LinkedIn.

His career includes key government and political roles such as Managing Partner at Brighton Strategy Group (April 2025-present), Chief Spokesperson and Press Secretary for the U.S. Department of Defense (January-April 2025), Deputy Assistant to the President and Senior Director for Strategic Communications at the National Security Council (White House, under President Trump), Assistant Secretary for Public and Intergovernmental Affairs at the U.S. Department of Veterans Affairs (2017-2019), Senior Advisor for the 2016 Trump Presidential Campaign (communications and state/local media), Communications Director and Senior Policy Advisor for U.S. Senate Committees on Armed Services and Veterans' Affairs (approx. 2003-2007), and Senior Adviser to Senators Arlen Specter and John W. Warner. In the private sector, he has held positions including Managing Director at High Lantern Group (2013), Senior Vice President at Hill & Knowlton Strategies (lobbyist, Global Corporate Practice), Acting Global Head of Relations at DuPont, Vice President of Corporate Communications at AOL Europe, and Washington Spokesman at Intel.

Ullyot is the author of The Biden-Harris Betrayal: Weak and Woke on the World Stage (Amplify Publishing Group, August 20, 2024), a collection of 50 essays criticizing Biden-Harris policies. He is a columnist at Townhall and has contributed op-eds to the Wall Street Journal, New York Post, National Review, Federalist, and Politico (e.g., April 20, 2025, criticizing Pentagon 'chaos' under Pete Hegseth).

Controversies include: At the VA (2018-2019), he was accused of plotting to oust Secretary David Shulkin amid a travel scandal, lobbied Congress for Shulkin's resignation believing Trump would fire him, and resigned on March 14, 2019, as an embattled Trump appointee. As Pentagon Press Secretary in 2025, he oversaw the removal of DEI-related content from DoD websites in March 2025, including a Jackie Robinson tribute page and pages on Navajo code talkers, which he defended as combating 'Woke cultural Marxism' but was criticized as racist; this sparked backlash, leading to him being sidelined late March and asked to resign in April 2025 amid upheaval under Defense Secretary Pete Hegseth.