The 30-year-old signed a three-year deal with PSG.
"Signing for Paris Saint-Germain is a new challenge for me," Wijnaldum said. "I'm joining one of the best squads in Europe and I want to bring all my desire and commitment to this ambitious project.
"Paris Saint-Germain have proved how good they are in recent years and I am convinced that together, with our supporters, we can go even further and higher."
Wijnaldum joined Liverpool from Newcastle United in 2016 and won the Champions League, Premier League, UEFA Super Cup, and FIFA Club World Cup over his five-year stay with the Merseyside club.
Prior to his stint in England, he started out in Sparta Rotterdam's academy before representing Feyenoord and PSV Eindhoven early in his professional career.
Wijnaldum has collected 75 Dutch caps and will line up alongside Barcelona's Frenkie de Jong in midfield at the upcoming European Championship. The Netherlands will face Austria, North Macedonia, and Ukraine in Group C.