Some 13 years after he was deposed in a coup and sent into exile, the 63-year-old was formally chosen by a vote in the National Assembly on Wednesday and will take the oath from President Asif Ali Zardari later in the day.
Sharif also made a short speech to the National Assembly, where his Pakistan Muslim League-N (PML-N) holds a majority of the 342 seats, setting out his view on the problems facing the country.
Sharif demanded an end to US drone strikes in Pakistan.
Party officials say he is likely to lay out government priorities but not go into policy in any great detail, with a longer address to the nation expected in coming days.
The new premier has said tackling energy shortages, which rob the Pakistani economy of up to four percent of GDP, will be a priority and he has vowed to build new power plants.
PML-N scored a comfortable win in the May 11 general election as Zardari's Pakistan People's Party (PPP) was routed, blamed by voters for five years which saw the hated power shortages worsen and militancy continue almost unabated.
But the very fact that the PPP completed its five-year term was seen as important in a country that has suffered three coups and been ruled for more than half of its 65-year history by the military.