John Abraham Godson, 40, will have a seat in the lower house. He's a member of the ruling Civil Platform party.
Godson, a councilman in the central city of Lodz, was appointed to the seat being vacated by a lawmaker elected mayor of Lodz earlier this month, the BBC said.
Godson arrived in Poland some 17 years ago, opening an English-language school and serving as a pastor in a Protestant church, according to the BBC. He is married to a Polish woman, and they have four children.
Earlier, Godson called his appointment a "historic moment" for Poland and said he would work to boost ties with Africa and support technological innovation, according to The Associated Press.
Godson said he was beaten up twice in the early 1990s in Poland, where it's still rare to see black people and racism is still a problem, the BBC reported. But Godson said feelings toward black people are evolving, especially since the nation joined the European Union six years ago.