Army Secretary Ryan McCarthy resigned from his post Wednesday as the Biden administration was sworn in, with John Whitley, the service’s comptroller, to take over in an acting capacity.

McCarthy, who has steered the Army’s extensive modernization overhaul over the last several years, wrote in his farewell message to the force that he “will continue to be an advocate for the Army team.”

Secretary of the Army Ryan McCarthy speaks at the Brookings Institution in Washington D.C., Jan 10, 2020. (U.S. Army photo by Sgt. James Harvey)

Both in his role as under secretary since 2017 and then secretary of the Army, McCarthy was an advocate for the service’s push to develop more than 30 new signature weapon systems over the next decade, from Future Vertical Lift platforms to the Optionally Manned Fighting Vehicle, that aimed to position the force for competition with Russia and China.

More recently, McCarthy spoke of “borderline contentious” divestiture decisions that will be required to continue fully funding the Army’s modernization effort.

Christopher Lowman, current acting principal deputy assistant secretary for Acquisition, Logistics and Technology (ASA (ALT)), is set to step in as the acting under secretary for James McPherson.

Bruce Jette, the Army’s top acquisition official, has also stepped down and will be replaced for the time being by Lt. Gen. Bob Marion, the current principal military deputy at ASA (ALT). 

The Army will now have a new suite of leaders as it prepares to detail its latest round “night court” cuts to shift funds from legacy programs toward modernization efforts, and navigates major weapons programs that are heading toward critical milestone decisions and prototype development.