The new chiefs who initially served within the general command of the army will now deputize the Chief of Defense Forces, General James Ajonga Mawut.
In a republican decree issued on Wednesday, President Kiir appointed six assistant chiefs of the defense forces and five service commanders.
The new appointments are derived from officers who are already serving in various capacities within the army general command at Bilpam, and Presidential Guards.
President Kiir appointed First Lieutenant General, Malek Reuben who was serving as the Deputy Chief for Training, as the new Assistant Chief of Defense Forces.
Lieutenant General, Dr. Malual Ayom who was the Deputy Chief of Staff for Inspection has been appointed as the Assistant Chief of Defense Forces for Operations, Training, and Intelligence.
Lieutenant General Mangar Abuong who was serving as the Deputy Chief of Staff for Operations has been appointed as the Assistant Chief of Defense Forces for Administration, Fiscal, and Finance.
In the new position for Assistant Chief of Defense Force for Logistics and Procurement is Lieutenant General Gabriel Jok Riak who initially served as Sector One commander in Wau.
The former commander of the Presidential Guards, Lieutenant General Marial Chanuong has been appointed the new commander of Ground Forces and deputized by Lieutenant General Johnson Juma.
Both Marial Chanuong and Jok Riak are among senior South Sudanese commanders sanctioned by the United Nations.
In other appointments, President Kiir made Lieutenant General Charles Lam Chol, as the new commander of Air Force and Air Defense Forces.
He will be deputized by Lieutenant General James Kong Kong.
Lieutenant General James Gai Yoach was appointed as Commander of the Riverine Unit.
In a separate decree, Kiir also appointed Beny Gideon Mabor as the new chair of the South Sudan Human Rights Commission.