The far-right Freedom Party has secured the key posts of foreign, interior and defence in Austria's new coalition government for its nominees.
Governing with the conservative People's Party, the move makes Austria the only country in Western Europe to have a far-right party in power.
Austria's president approved the new coalition on Saturday, two months after inconclusive elections.
People's Party leader Sebastian Kurz, 31, will be Austria's new chancellor.
He will become the world's youngest head of government.
Introducing the new government, and the 180-page document setting out its agenda, Mr Kurz said the two parties had agreed "on a clear pro-European outlook".
Although it is the junior coalition partner, the anti-immigration Freedom Party has secured several key posts in the new cabinet.
Party leader Heinz-Christian Strache will be vice-chancellor. His party colleagues will run the interior, defence and health and social security ministries.
The new foreign minister will be Middle East expert and writer Karin Kneissl, who is not a Freedom Party member but was nominated by the party.
Mr Kurz's People Party won 32% of the vote in October's elections, securing the largest number of seats (62) in the 183-seat national council.
The Freedom Party came third, securing 26% of the vote and 51 seats.
At the request of Austria's president, the posts of justice minister and interior minister would not be held by the same party, Mr Kurz said.
The chancellor-designate was quick to retweet congratulations from his fellow youthful conservative prime minister, Ireland's Leo Varadkar.
Key posts in right-wing hands
Analysis by Bethany Bell, BBC News, Vienna
Unlike most of Europe's populist parties, the Freedom Party, a major player in Austria for years, has managed to translate its success at the ballot box into real political power.
That's reflected in the key posts that it has secured in this government: the interior, defence and foreign ministries.
The opposition has expressed concern that the police and the security apparatus are now all firmly in the hands of the Freedom Party.
In recent years, the party has toned down some of its more extreme rhetoric. But many analysts believe that, in or out of government, it has helped set a right-wing agenda, not just in Austria - but in other countries across Europe as well.
When the far-right Freedom Party last entered a coalition in Austria in 2000, its fellow EU member states froze bilateral diplomatic relations in response.
They were lifted months later, and such measures are unlikely to happen again, as resurgent right-wing populist groups have been promoting anti-immigration and Eurosceptic agendas across much of the EU.
But unlike the Freedom Party, those other parties have struggled to convert electoral success into real power:
- Earlier this year, Marine Le Pen's far-right National Front party lost the French presidential election comprehensively. Ms Le Pen was defeated by Emmanuel Macron, a liberal centrist and strong supporter of the European Union
- Elsewhere, the Dutch anti-immigration Freedom Party of Geert Wilders was defeated by liberal leader Mark Rutte
- In Germany, the nationalist and populist right of Alternative for Germany (AfD) gained seats in the national parliament, where it is now the third biggest party, but it is not in the frame for coalition talks
Who's who in the new government?
Chancellor: Sebastian Kurz, People's Party. The 31-year-old was foreign minister in the outgoing Austrian government.
Interior minister: Herbert Kickl, Freedom Party. The party's general secretary and campaign director, 49, was a speechwriter for the late party leader Jörg Haider and is a close confidant of the current leader, Heinz-Christian Strache.
Foreign minister: Karin Kneissl, nominated by the Freedom Party but not a member. The former foreign ministry employee and Middle East expert, 52, speaks eight languages and is not afraid of controversy, according to Austrian media.