Secretary of the Army Mark T. Esper, the man who made the case for the Army’s renaissance, will become acting secretary of defense, President Donald Trump announced June 18.

Esper will fill the job as Acting Defense Secretary Patrick Shanahan is taking himself out of contention to become the permanent secretary. Trump said Shanahan has done a “wonderful job” since stepping in on Jan. 1 to replace retired Marine Gen. James N. Mattis in the top Pentagon post but now wants to spend more time with his family.

Shanahan’s nomination for the permanent defense secretary job had never been sent to the Senate for consideration.

Esper, who has served as Army secretary since Nov. 20, 2017, is a former infantry officer who has also served in the Army National Guard and Army Reserve. He retired as a lieutenant colonel. He is a former Raytheon executive who also worked for the Aerospace Industries Association and as a congressional staff member.

A strong advocate for leap-ahead modernization, Esper has expressed a sense of urgency in getting the Army to move. “We must act now to ensure we are ready today and even more lethal tomorrow,” he said at the October 2018 Association of the U.S. Army Annual Meeting and Exposition. “We are in a renaissance,” he said. “This renaissance means we look at everything differently. We turn it upside down and inside out.”

The move by Trump means yet another change to the Army’s top leadership ranks. Army Chief of Staff Gen. Mark A. Milley has been announced as Trump’s pick to be the next chairman of the Joint Chiefs; his confirmation hearing before the Senate is still pending.

Army Vice Chief of Staff Gen. James C. McConville has been confirmed to be the next chief, while Lt. Gen. Joseph Martin will become the next vice. Also on the way is a new senior enlisted soldier for the Army—Command Sgt. Maj. Michael A. Grinston has been selected to succeed Sgt. Maj. of the Army Daniel A. Dailey.