Jon Harrison is an American defense official who served as Chief of Staff to the Secretary of the Navy from January 2025 until his dismissal on October 3, 2025, by Defense Secretary Pete Hegseth. A key figure in the Trump administration’s military restructuring, he played a major role in reorganizing the Navy’s policy and budgeting offices.
With a long career in national security and defense strategy, Harrison was seen as a trusted insider. His removal after the confirmation of Navy Undersecretary Hung Cao has drawn attention to internal tensions within the Department of Defense.
Jon Harrison Wiki/Bio
| Full Name | Jon Harrison |
| Profession | Defense Official, National Security Advisor |
| Nationality | American |
Jon Harrison Career Highlights
Jon Harrison built a strong reputation in national security and defense leadership over the years. His most prominent appointment came in January 2025, when he became Chief of Staff to the Secretary of the Navy, working alongside Secretary John Phelan.
In this role, Harrison oversaw bureaucratic restructuring, which included consolidating policy and budgeting offices to improve efficiency and control under the Trump administration. Prior to that, he served as Chairman of the United States Arctic Research Commission (2020–2021), appointed by President Donald Trump, focusing on strategic U.S. interests in the Arctic region.
His tenure as Chief of Staff was marked by administrative streamlining and close coordination with top defense officials. However, his removal in October 2025 followed reports of internal disagreements after the confirmation of Undersecretary Hung Cao.
Career Milestones
| Milestone | Details |
| Arctic Research Chairman | Led the U.S. Arctic Research Commission (2020–2021) |
| Chief of Staff Appointment | Joined Navy Secretary John Phelan’s office (January 2025) |
| Bureaucratic Reorganization | Directed policy and budgeting consolidation (2025) |
| Aide Reassignments | Oversaw reassignments ahead of Undersecretary Cao’s arrival (2025) |
| Dismissal | Fired by Defense Secretary Pete Hegseth (October 3, 2025) |
Jon Harrison Controversies
Jon Harrison’s dismissal on October 3, 2025, attracted significant attention in defense circles. Reports suggest tensions arose between Harrison and leadership following the confirmation of Navy Undersecretary Hung Cao, with disagreements over personnel and departmental control.
Harrison and Secretary John Phelan reportedly reassigned aides and planned internal restructuring to align with their operational strategy. Defense Secretary Pete Hegseth’s decision to fire Harrison came amid broader administrative realignments in the Department of Defense.
🇺🇸 Defense Secretary Pete Hesgeth has fired Navy chief of staff Jon Harrison [pictured], following the confirmation of Navy Undersecretary Hung Cao.
— Vanguard Intel Group 🛡 (@vanguardintel) October 3, 2025
Harrison, a Trump appointee with unusual influence, and Navy Secretary John Phelan had restructured the Navy’s bureaucracy,… pic.twitter.com/khN5IxUuCb
There are no records of personal misconduct or ethics violations linked to Harrison. His firing appears to have been a result of bureaucratic and political friction rather than scandal.
Sources
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