McKenzie's general officer posts have included Deputy Director of Operations for the National Military Command Center in the Pentagon.

He returned to Afghanistan serving as Deputy Chief of Staff for Stability under the International Security Assistance Force,[9] followed by a tour as Director of Strategy, Plans and Policy at United States Central Command.

[10] As CENTCOM commander, McKenzie oversaw the successful high-profile special forces raid in Syria to kill or capture then-Islamic State leader Abu Bakr al-Baghdadi in October 2019,[11] and the 2020–2021 withdrawals and reductions of U.S. troops from Iraq.

"[13] One month later, McKenzie was responsible for the August 2021 Kabul drone strike which targeted and killed civilians, 7 children and 3 adults.

[14] McKenzie retired from active duty on 1 April 2022, after relinquishing command of CENTCOM to General Michael Kurilla.