Who was the youngest command officer to be the Chairman of the Joint Chiefs of Staff?

Colin L. Powell served as Chairman of the Joint Chiefs of Staff from 1989 until 1993. Powell was 52 years old when he became the youngest officer, and first Afro-Caribbean American, to serve in the position as Chief. He was also the first JCS Chairman who received his commission through ROTC.

During his tenure, he oversaw 28 crises, including the invasion of Panama in 1989 to remove General Manuel Noriega from power and Operation Desert Storm in the 1991 Persian Gulf War. During these events, Powell earned his nickname, the reluctant warrior. He rarely advocated military intervention as the 1st solution to an international crisis, and instead usually prescribed diplomacy and containment.

It was President George H. W. Bush who selected Powell as Chairman of the JCS. Powell continued as Chairman of the JCS into the Clinton presidency, but as a dedicated "realist" he considered himself a bad fit for the new administration.

Ultimately, Powell returned to private life in 2005.