However, since the establishment of the National Command Authority (NCA), the army has staked a claim to its leadership, because it controls the key areas of nuclear command and strategic assets.
The CJCSC is also the deputy chairman of NCA's deployment committee, which is headed by the prime minister.
General Zubair Hayat is from the artillery and was serving as Chief of General Staff (CGS) prior to taking over as CJCSC.
Given his career trajectory, General Hayat was always expected to become the CJCSC.
As a three-star general, he was previously posted as director general of the Strategic Plans Division (SPD) - which is the secretariat of the NCA - and corps commander Bahawalpur. This made him an ideal choice for the post of CJCSC, who has an almost exclusive jurisdiction over nuclear forces and assets.
His stay at the directorate and his earlier posting as principal staff officer to the army chief brought him closer to General Kayani, and he is generally seen as General Kayani's protege.
His postings as CGS and DG SPD afforded him an opportunity to work very closely with PM Nawaz Sharif and Finance Minister Ishaq Dar.
During his tenure as a major general, he was general officer commanding (GOC) Sialkot and later headed the Staff Duties (SD) Directorate, whose personnel are commonly known in the army as 'paper tigers'.
Some of those who worked with him describe him as workaholic and a voracious reader. He is also said to have a very sharp memory.