Fellow Pole Wajda, who won a lifetime achievement Academy Award in 2000, is helming the movie, which will tell the story of how Walesa and his Solidarnosc trade union helped crush communism in Eastern Europe.
The filmmaker, who will use archive footage of Walesa for some scenes, admitted it will be "the most difficult movie I have made in my life" but added that his subject is supporting the project.
Polish actor Robert Wieckiewicz, who will play Walesa in the film, says he faces a tough task in bringing the charismatic leader to life onscreen, adding: "He's one of the best-known Poles. I think there are dozens of Walesa experts in Poland and each of them will have their own opinion."
Walesa won the Nobel Peace Prize in 1983 and served as president of Poland from 1990 until 1995.