Malcolm O’Neill, chief of acquisitions for the U.S. Army, is resigning effective Friday because of personal reasons after a little more than a year in the job, Army officials said Thursday.

Heidi Shyu, currently the principal deputy, will serve as acting chief upon O’Neill’s resignation as Assistant Secretary of the Army for Acquisition, Logistics and Technology, according to the Army.

“I respect Dr. O’Neill’s decision to step down for personal reasons and wish to express the Department’s sincere gratitude for his service,” Army Secretary John McHugh said in a statement Thursday. “At a critical time in our acquisition efforts, Mal

has brought a mature and steady hand to the challenges we face. His efforts and cooperation in the development and ongoing implementation of recommendations from the Army Acquisition Review have been critical to our establishing a better path forward. Mal has served with distinction, both as a career Army officer and as the Army’s Acquisition Executive, and we wish him well.”

As acquisitions chief, O’Neill was responsible for the management and sustainment of Army weapons systems and equipment from research and development through test and evaluation, acquisition, logistics, and fielding.

O’Neill, who was nominated to the position by President Obama, was sworn into office March 10, 2010. Before retiring as a three-star general, O’Neill had served as director of the Ballistic Missile Defense Organization as well as director of the Army Acquisition Corps. After retiring, he served as Vice President and Chief Technical Officer at Lockheed Martin Corporation.

Defense News, which first reported O’Neill’s departure, quoted a source as saying that O’Neill is leaving for a health-related reason.

“It has been my great privilege to lead the Army Materiel Enterprise, a hard working team dedicated to the success of our Soldiers at war and in operations throughout the world,” O’Neill said in a May 31 memo to his staff quoted by Defense News. “I have witnessed firsthand the difference we make in providing the American Soldier, our most important customer, with world-class weapon systems and equipment. I am grateful for the many opportunities I have been given during my career and especially in my current position. I have enjoyed my time here, and I wish you every success in the future.”