The mainly ethnic Albanian parliament of the United Nations-administered province on Wednesday approved Bajram Kosumi and his new cabinet by 71 votes to 36.
The vote makes him leader in the year that the UN is to open talks on Kosovo's status and potential independence, after almost six years in limbo.
Kosumi, 45, is the handpicked successor of ex-prime minister Ramush Haradinaj, 36, the former Kosovo Liberation Army (KLA) commander who resigned this month to answer charges of war crimes at the Hague tribunal.
The new government is the first since the war of 1998-99 to have no former guerrillas as members. Kosumi was sentenced to 15 years in prison for organising ethnic Albanian protests against Serb rule in 1981, but while he later supported the KLA insurgency he did not take up arms or wear uniform.
Task cut out
The Democratic Party of Kosovo, led by former guerrilla commander Hashim Thaci, voted against the appointment.
Considered a moderate among Kosovo politicians, Kosumi has in his own words "invested my past 26 years in the creation of the state of Kosovo".
"We are going to achieve independence sooner than anyone else could," Kosumi pledged recently.
"Independence for Kosovo cannot be won by votes. It's a historic issue for which we need consensus among all"
Kosovo's interim Prime Minister
He comes to office on the date when, 16 years ago, former Serbian strongman Slobodan Milosevic revoked Kosovo's autonomy, setting in motion the events that led to Nato intervention in 1999.
Kosovo's 90% ethnic Albanian majority wants independence, which Serbia is not prepared to grant. But Belgrade lost control of Kosovo six years ago, and the UN will decide its future status.
Haradinaj was a former migrant construction worker and nightclub bouncer who became a guerrilla commander when the KLA took on Serb forces in 1998-99.
Kosumi, a graduate in Albanian literature, is a quieter, more cerebral politician, appreciated for his concentration and focus as a member of the negotiating team at the Rambouillet peace conference in early 1999, prior to Nato's 11-week bombing to drive Serb forces out of Kosovo.
Observers said one possible question mark would be his leadership style in a coalition cabinet where Haradinaj's forceful character kept factions in check.
Ex-PM Haradinaj is in Hague to
answer charges of war crimes
The new prime minister, who was information minister in the first interim government led by Thaci, is an ally of veteran politician Adem Demaci, the man venerated as "Kosovo's Mandela" for his 28 years as a political prisoner.
"Independence for Kosovo cannot be won by votes. It's a historic issue for which we need consensus among all," Kosumi said before the vote in a gesture to Kosovo's Serb minority, urging ethnic Albanians to "welcome the return of all".
Up to 200,000 Serbs fled when Nato occupied Kosovo in the summer of 1999, fearing revenge attacks by Albanians.