Hailed by mass circulation daily Bild as an "election sensation", the party clinched around nine percent of the vote in Sunday's regional poll in Berlin, which was won by the Social Democrats and their popular mayor, Klaus Wowereit.
The Pirates, a youth movement with origins in Scandinavia and now active in around 20 countries, has been in Germany for five years and is beginning to shed its image as a "party for geeks."
The election win has thrust the party, and its leader, into the limelight.
"From IT-nerd to full-time politician," said the Financial Times Deutschland online edition introducing a profile of Andreas Baum, the head of the group.
Its supporters and leaders are young and well-educated – most of those who voted for the party were under 30, according to an election analysis by television channel ZDF.
"Ask your children why you should vote for the Pirates," runs one of its election posters. "We have the questions, you have the answers," says another.
Thirty-three-year-old telecoms engineer Baum, who was chosen by lot, told ZDF after the results: "We're going to get to work ... people will hear from us, of that you can be sure."
"Our grace period is over," Matthias Schrade, another senior member told AFP after the results. "Now we have to show that we want to get things moving," added Schrade, one of around 1,000 Pirates gathered in the grungy Berlin district of Kreuzberg to celebrate the results.
The party can expect to secure around 15 seats in the 130-seat Berlin regional parliament, according to initial calculations.
Campaigning mainly via the Internet, the Pirates spent less than a quarter of the €1.7 million ($2.3 million) shelled out by the victorious SPD party.
Their manifesto can be summed up in one word: "Transparency."
"We want to make public all data, all administrative procedures," said Martin Delius, a 27-year-old IT engineer.
On their online editions, major German dailies focused nearly as much on the Pirates as the winners of the election.
"The election success in Berlin will give the Pirates a powerful tailwind," commented the Freie Presse daily.
"If the political rising stars manage to sail nicely with the wind and get competent people at the wheel, then (Sunday's) victory may be more than just a warning shot," the paper added.
Observers put the Pirates' success down to a protest vote at mainstream politics, a theme echoed by Simon Weiss, a 26-year-old mathematics student and party supporter.
"The way politics is done annoys me," he said. "Either I do something myself, or nothing will happen", added Weiss, who described himself as a political "idealist."
What all Pirates have in common is a desire for "better politics," he said. "There are plenty of people who think like me."
But other observers castigated the established parties, especially Chancellor Angela Merkel's junior coalition partners, the Free Democrats (FDP), for allowing such a party into the parliament.
"If the situation in the country were not so serious, you could put the success of the Pirate party down as a 'Berlin speciality'. In other words: Things are just a little bit different in the capital," said the Rhein Zeitung daily.
"But in fact, the Pirates' victory makes a mockery of the established parties. Apart from the Pirates, no one should be celebrating this election, least of all the FDP.
According to partial results from Berlin, the FDP were the big losers in Sunday's election, being ejected from the parliament with a mere 1.8 percent of the votes cast.