Lieutenant-General Raheel Sharif’s ascent to Pakistan's top military job is something of a surprise.
It was widely understood the outgoing chief, General Ashfaq Pervez Kayani, wanted the more senior Lieutenant-General Rashid Mahmood to take the post. Instead, Mahmood - a close confidant of Kayani - was given the role of Joint Chiefs of Staff Committee, a technically superior but largely ceremonial role.
Raheel Sharif is a career infantry soldier and the military's third most senior officer. Little else is known about him apart from the fact his brother was one of the army's most decorated soldiers and was killed in the 1971 war with India.
He is also believed to be close to Prime Minister Nawaz Sharif's family but is not a relative. Talat Masood, a retired major-general, says Sharif’s appointment could reinvigorate the country’s military.
"Every commander is different. He will bring in a different atmosphere and a different way of working," Masood says. "Some of the old policies will likely continue, but his way of working will be different."
Raheel Sharif's reputation as a professional soldier with no obvious political ambitions possibly played a major factor in his selection by Nawaz Sharif.
Nawaz Sharif, who served as prime minister twice before, has had difficult experiences with appointing army chiefs.
During his second term in office, he appointed General Pervez Musharraf.
But Musharraf overthrew his government in a coup in 1999, resulting in nine years of military rule - something Masood says Nawaz Sharif is keen to prevent from happening again.
"I think he wanted to be absolutely certain and extremely confident the next person chosen as chief of army staff would not destabilize the civilian government and try to restore the civil-military balance which has always been in favour of the military," Masood says.
"And I think he wanted to be able to assert himself over the military, and that I think was his prime consideration."
The transition comes as Pakistan is preparing for the fallout from the withdrawal of US-led coalition troops from Afghanistan at the end of 2014.
The US military and government see Pakistan's cooperation as vital to Washington's strategy in the region.
Raheel Sharif is expected to continue with Kayani's policies to avoid overt interference in politics and with assisting the US as it withdraws from Afghanistan.
But Pakistan has been ruled by the military for more than half of its 66 year history, which means there are no guarantees another military takeover can be ruled out.