The Army's chief of public affairs is moving on to serve as the senior military assistant to Defense Secretary Ash Carter.

Maj. Gen. Ron Lewis took over the Army's public affairs office in June. His move isn't official yet, but he will be the new senior military assistant to Carter, who was sworn in Tuesday, a defense official speaking on background confirmed to Army Times.

Lewis, a career Air Cavalry officer, has spent a lot of time at the Pentagon between deployments.

He served as an adviser on Carter's transition team, and he has filled the role of military adviser to Carter twice before.

Lewis was Carter's military assistant when Carter was the undersecretary of defense for acquisition, technology and logistics in 2011. He then served as senior military assistant when Carter took over as the deputy secretary of defense.

Lewis deployed to Afghanistan in early 2012, serving as the deputy commanding general for support for the 101st Airborne Division.

He also commanded the 101st Airborne's 159th Combat Aviation Brigade on a previous deployment to Afghanistan, and led units from the 1st Cavalry Division in Iraq.

A graduate of West Point, Lewis also trained aviation and cavalry units twice at the National Training Center at Fort Irwin, California, and served in several operational assignments across the United States, Europe and Korea.