The Chief of the Defence Staff (CDS) was the most senior appointment in the Sri Lankan Armed Forces, and the highest-ranking military officer in service, outranking the heads of each service branch.

The CDS was the Chairman of a Committee made up of service commanders and is a member of the National Security Council.

The Chief of the Defence Staff was appointed to the highest rank in the branch of the Sri Lankan armed forces to which he belonged (equivalent to a British "four-star" rank) being a General, an Admiral or an Air Chief Marshal.

According to the new Bill, the president of Sri Lanka appointed to the post of Chief of Defence Staff any person serving as Commander of the Army, Navy or the Air Force, to function under the direction, supervision and control of the permanent secretary to the Ministry of Defence.

The CDS was assisted by a chief of staff (two-star rank) and four director generals (operations and systems, training, naval and air operations, coordination) made up the Office of the Chief of the Defence Staff.