Chief of Staff

American  

noun

1. the senior officer of the U.S. Army or Air Force, a member of the Joint Chiefs of Staff, responsible to the secretary of a service branch.

2. (lowercase) the senior or principal staff officer in a brigade or division or higher unit in the U.S. Army or Marine Corps, in a numbered unit in the U.S. Air Force, or in a unit in the U.S. Navy commanded by a rear admiral or one of higher rank.

3. (lowercase) the senior officer in command of a general staff, especially that of the military forces of a nation.

4. (lowercase) the head of any staff.

   the chief of staff for the First Lady.

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Chief of Staff British  

noun

1. the senior staff officer under the commander of a major military formation or organization

2. the senior officer of each service of the armed forces

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Etymology

Origin of Chief of Staff

First recorded in 1880–85

Example Sentences

But Army Secretary Dan Driscoll and acting Army Chief of Staff Christopher LaNeve acknowledged during their testimony on Friday that they were only told the deployment had been canceled a couple of days ago.

From The Wall Street Journal • May 15, 2026

White House Chief of Staff Susie Wiles will convene a meeting this week to "discuss protocol and practices for major events", the official also said.

From BBC • Apr. 27, 2026

General Christopher LaNeve is set to become acting Chief of Staff of the US Army, according to CBS News, the BBC's US partner.

From BBC • Apr. 3, 2026

And the lack of churn has also been credited to White House Chief of Staff Susie Wiles, who by most accounts has enforced significant restraint from a famously chaotic leader.

From Slate • Apr. 3, 2026

Kissinger started pounding the table with his fists, yelling directly at Chief of Staff Bob Haldeman.

From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin