General Ashfaq Pervez Kiyani on Thursday assumed charge as chief of the Pakistan army following the retirement of President Pervez Musharraf, who held the post for over nine years.
Kiyani reviewed a guard of honour at the army's general headquarters in the garrison city of Rawalpindi before formally assuming office.
Musharraf stepped down as army chief on Wednesday. The military ruler had in October promoted Kiyani, a former chief of the powerful Inter-Services Intelligence agency, to the rank of general and named him as his successor.
The defence ministry on Wednesday notified Musharraf's retirement and Kiyani's appointment.
Kiyani is the first ISI chief to command the 500,000-strong army. The chain-smoking general rose rapidly through the ranks after playing a key role during the 2001-02 stand-off between India and Pakistan, when the two countries mobilised close to a million troops along their border following a terrorist attack on India's Parliament.
Then director general of military operations, Kiyani was in charge of troop movements and experts said his deft handling of the situation prevented the stand-off from taking a turn for the worse.
Kiyani hosted a farewell dinner on Wednesday night for Musharraf, who was appointed army chief by former prime minister Nawaz Sharif in 1998.
Military spokesman major general Waheed Arshad said the change of guard would not affect Pakistan's commitment to the war on terror. He dismissed speculation in this regard, saying the Pakistan army was committed to eliminating terrorism and extremism.