Kaczynski, who combines traditional, Catholic values with scepticism about free-market economics, won the Sunday run-off against pro-business moderate Donald Tusk on a promise to root out corruption and protect the welfare state.
The zloty dipped briefly on Monday, reflecting market concern the victory of the tough-talking Warsaw mayor gives extra clout to his Law and Justice party, sceptical about deep fiscal and market reforms.
The currency quickly regained ground reflecting hopes for a coalition deal this week.
Law and Justice won last month's general elections after denouncing Tusk and his Civic Platform for their tax-cutting plans and making lavish campaign promises to farmers and heavy industry workers.
The double victory is a sweet reward for Kaczynski and his identical twin brother Jaroslaw, Law and Justice chairman, after years of never quite making it to the top in politics.
They face a formidable task trying to win over Poland's growing middle class, which overwhelmingly backed Tusk, as well as Poland's EU partners irked by the Kaczynskis' mild nationalism and anti-gay remarks.
The new president-elect, who will formally replace outgoing leftist Aleksander Kwasniewski in December, struck a conciliatory tone in his first remarks after official results showed he won the presidency with 54 percent of the vote.
"I want to pass my best wishes and words of respect and sympathy to my rival Donald Tusk," he said. "My Law and Justice colleagues and I are definitely in favour of a joint government (with the Platform)."
TALKS RESUME Talks between the two parties, heirs to the pro-democracy Solidarity movement that toppled communism in 1989, resumed in earnest on Monday after grinding to a halt during the presidential campaign.
The conservative prime minister-designate Kazimierz Marcinkiewicz said he hoped to conclude the talks by Wednesday and to form a cabinet by Saturday.
Signalling a U-turn from the party's campaign rhetoric which portrayed the Platform as dangerous free-market zealots, he and other Law and Justice officials were at pains to prove the two parties were not that far apart on the economy.
Marcinkiewicz vowed the government would be built around Law and Justice's pledge of "social solidarity" and the Platform's drive to lower taxes and cut red tape in a bid to spur growth and reduce 18 percent unemployment, the EU's highest.