Lech Kaczynski, mayor of Warsaw since 2001, has won respect for cracking down on crime and for a no-nonsense style that has brought him a reputation as a rare politician with the courage to say what he thinks.
His opponents, however, view him as narrow-minded, provincial and overzealous in his drive to cleanse the country of the influence of former communists. And he drew criticism from human rights groups this summer for trying to stop a gay-rights parade through Poland's capital.
Kaczynski's tough stand against crime when serving as justice minister in a previous center-right government in 2000-2001 laid the foundations for his current popularity. He is a leading member of the Law and Justice party, which he and his twin brother, Jaroslaw, founded in 2001.
Kaczynski has made clean government a key pledge a promise that resonates after a string of corruption scandals that saw the ex-communist Democratic Left Alliance swept from power in parliamentary elections last month.
During the presidential campaign, Kaczynski narrowed a double-digit lead held by center-right rival Donald Tusk by criticizing his market-oriented economic proposals. Kaczynski argued that ideas such as a flat-rate income tax would benefit only the rich.
Lech Kaczynski is a former child movie star who first won fame with his twin in a hit movie, "Two Who Stole the Moon," about two troublemakers who try to get rich by stealing the moon and selling it. That was the end of their film career, however.
In the 1970s and 1980s, the Kaczynski brothers were activists in the anti-communist opposition and went on to serve as advisers to Solidarity founder Lech Walensa.