Tsipras took a civil oath "to uphold the constitution and laws" of the country, and is expected to name a coalition government by Wednesday to begin applying the terms of the tough eurozone bailout he reluctantly agreed to in July.
Lauding the result that saw his leftist Syriza party returned to power, Tsipras, said he now had a “clear mandate” to govern, adding, “Today in Europe, Greece and the Greek people are synonymous with resistance and dignity. This struggle will be continued together for a full four years,” he said.
He made no specific reference to the 86 billion euro ($97 billion) bailout of his country from eurozone creditors. But Syriza campaigned on a pledge to implement it — areversal of its previous position — while promising also to introduce measures to protect vulnerable groups from some aspects of the deal.
“We have difficulties ahead of us but we also have a solid ground, we know where we can step, we have a prospect. Recovery from the crisis can't come magically, but it can come through tough work,” he said.
At 41, Tsipras now dominates Greek politics, having seen off both the main, center-right opposition and his own party rebels despite a sharp policy U-turn that kept the country in the eurozone but ditched the anti-austerity platform that had first swept him to power in January.
Syriza’s leader quickly announced that he will renew his pro-European coalition with the small, right-wing populist Independent Greeks (ANEL) party, which beat opinion polls to clear the three percent parliamentary entry threshold.
With more than 99.7 percent of Sunday's votes counted, Syriza had 35.5 percent, while New Democracy trailed with 28.1 percent. But in a sign of widespread discontent, more than four in 10 Greeks stayed away from the parliamentary election — the second this year — and the far-right Golden Dawn remained the country's third-strongest party with 7 percent.
Just two months ago, Syriza abandoned its pledges to reverse income cuts, tax hikes and labor reforms under duress to secure a third international bailout for the recession-battered country. Tsipras has promised to put as human a face as possible on the inevitable new cutbacks and pension reforms his government must enforce to continue receiving the rescue loans.
“We will soften certain elements of the agreement, without breaking our [bailout] commitments,” Dimitris Mardas, deputy finance minister in Tsipras' first government, said Monday.
Many Greeks voiced apprehension over the impending cutbacks, which follow a six-year wave of austerity measures that lopped a quarter off the economy and saw unemployment rise to 25 percent.
“I am happy that Tsipras was elected, but he should work,” said 54-year-old mechanic Kostas Tabaris. “He must [carry out] reforms, fix the crisis, help the poor, give presents, money to everyone.”
Civil servant Nikos Georgopoulos, 40, said he found the result disappointing.
“I am pessimistic, because we already knew which line of politics will be followed,” he said. “The politics of the third [bailout]. So we know that there is nothing good for the Greek people to wait for.”
Just seven months into his term, Tsipras lost his majority in parliament after far-left rebels in his party opposed the tough conditions demanded by eurozone countries for the new rescue package. But rebels, who formed a breakaway party pledging to take Greece out of the eurozone, failed to get elected to parliament.
The new government will have a small majority of just five seats — and little time to waste.
Creditors are expected to review progress of reforms as part of the bailout next month, while the government will also have to draft the 2016 state budget. It must also oversee a critical bank recapitalization program, without which depositors with over 100,000 euros ($113,000) in their accounts will be forced to contribute.
A total of eight parties won parliamentary seats, including the once-dominant Socialist Pasok, centrist Potami, the Greek Communist Party and the Centrist Union.
Golden Dawn, whose leadership is on trial for allegedly running a violent criminal group, dropped marginally in its number of ballots, but had a slightly higher percentage of the overall vote due to the low turnout.
The vote was held as Greece struggles to cope with Europe's refugee crisis, and Golden Dawn performed strongly on the eastern island of Kos, which has seen massive refugee arrivals from Turkey, almost doubling its percentage there to 10 percent.
Al Jazeera and wire services