|Katainen's National Coalition Party won the parliamentary elections for the first time in history in April [EPA]
Finland's parliament has voted for Jyrki Katainen as new prime minister, placing the outgoing finance minister at the head of a new six-party coalition.
Katainen's ministers had already been named and President Tarja Halonen ceremonially appointed the government after the vote in parliament on Wednesday.
"With a vote of 118 in favour, 72 against ... Jyrki Katainen has been elected prime minister," Ben Zyskowicz, the parliamentary speaker, announced.
The vote formally handed the prime minister's office to Katainen, 39, the head of the conservative National Coalition Party, more than two months after the April 17 elections put his party on top for the first time in Finnish history.
The comparatively young politician took over the party at the age of 33 and, in 2008, the Financial Times named him the best finance minister in Europe.
Katainen had struggled to form a coalition between six of the eight political parties from all sides of the parliamentary spectrum, insisting that Finland had to have a majority government.
"These parties had very different goals during the elections ... This is not a very cohesive coalition," Ilkka Ruostetsaari, a political analyst at Tampere University, told the AFP news agency.
"With the inclusion of the leftist parties, this government is clearly more left-leaning than [outgoing prime minister Mari] Kiviniemi's government, which means some change can be expected."
The core of the coalition comprises the conservative National Coalition and election runners-up, the Social Democratic Party, with each party holding six of the 19 ministerial posts.
The coalition is filled out on the right with the Swedish People's Party and the Christian Democrats and on the left by the Left Alliance and the Green League.
This left an opposition made up of only Kiviniemi's Centre Party and the nationalist True Finns.
The True Finns had surged to 39 seats in the 200-member parliament from only five after the previous election, having become the country's third largest party.