Defense Secretary Pete Hesgeth on Friday fired Navy chief of staff Jon Harrison, an unusually powerful top aide who had orchestrated a reshuffle of the service’s bureaucracy.

The sudden ouster, according to two defense officials and a former defense official, follows the confirmation this week of Navy Undersecretary Hung Cao.

The Pentagon, in a statement, confirmed Harrison’s departure. “He will no longer serve as Chief of Staff to the Secretary of the Navy,” it said. “We are grateful for his service to the Department.”

Harrison declined to comment.

The Navy secretary’s chief of staff has traditionally been a behind-the-scenes job, the senior aide who keeps everything moving smoothly. But Harrison, a Trump administration appointee who joined the service in January, had a rare level of power.

Harrison and Navy Secretary John Phelan had introduced sweeping changes to the Navy’s policy and budgeting offices and sought to limit the influence of the undersecretary job.

POLITICO previously reported that Phelan and Harrison had reassigned several aides who were supposed to help Cao navigate the role once he’s confirmed. They had also planned to interview all future military assistants for Cao to ensure decisions came from the secretary’s office.

Cao is a high-profile Navy veteran and former Republican Senate candidate in Virginia who President Donald Trump nominated for the post.

The ouster follows months of musical chairs inside the Pentagon. Hegseth fired several top aides earlier this year and removed the chair of the Joint Chiefs, as well as the uniformed leaders of the Navy, Air Force and Coast Guard.

Trump has vowed to revive the shipbuilding industry. But the service’s biggest programs are years behind schedule and both America’s allies and its largest adversaries are surpassing the productivity of U.S. shipyards.