Kaczynski was born in Warsaw in 1949. He and his twin brother, Jaroslaw, are child movie stars who won fame in the 1962 movie "The Two Who Stole the Moon," about two troublemakers who try to get rich by stealing the moon and selling it.
Kaczynski, 61, had been a law professor at Gdansk University from 1991 to 1997. Later he taught at the Law School of Warsaw University, where he graduated in 1971.
Kaczynski, a Solidarity activist, became a senator in 1991 after serving as a representative to the National Assembly since 1989.
He had been the country's prosecutor-general and justice minister in a previous center-right government before he was elected the mayor of Warsaw in 2002.
Kaczynski and Jaroslaw formed the socially conservative Law and Justice party in 2001 under the banner of developing the country's education and economy, fighting corruption and reforming rural areas.
Jaroslaw was nominated by Lech Kaczynski as prime minister on July 10, 2006.
