The film, directed by Andrzej Wajda and starring Robert Wieckiewicz as Walesa, is Poland's official entry for best foreign film at the Academy Awards.
It depicts the days in which Walesa founded the Solidarity trade union and helped lead the effort to end the country's communist regime 30 years ago. He served as president between 1990 and 1995.
Initially, Walesa, now 70, didn't like the movie.
"Especially my portrayal," Wieckiewicz said.
The former president said he found his portrayal to be too reductive, showing him only as a worker and father, and that "life was so much more bountiful than this."
Walesa -- who won the Nobel Peace Prize in 1983 -- told the Washington Post the movie got better each of the six or seven times he watched it.