The 34-year-old returns to his boyhood club as a free agent, having parted ways with Serie B side AC Monza this summer.
Boateng started his career at Hertha Berlin in 2004 and rose through the ranks to become a first-team player in 2006.
The midfielder left his boyhood club in 2007 for Tottenham Hotspur and has since played for different teams across Europe.
His journeyman career has seen him line up for Borussia Dortmund, Portsmouth, AC Milan, Las Palmas, Sassuolo, Barcelona and Besiktas.
However, Boateng has now sealed a move back to Hertha Berlin, where it all began for him.
A statement from the club said: “In 2006 he made his Bundesliga debut for Hertha BSC, now our homegrown team is back in his home country: Kevin-Prince Boateng returns to Berlin and wears the blue and white jersey again.”
“The attacking midfielder is moving from Italian Serie B team AC Monza to the Spree and signed a contract until 2022 on Thursday.”
Meanwhile, Boateng said Hertha Berlin means so much more to him than just a club, saying they’ll forever remain in his heart.
“Hertha BSC is not just any club for me. I'm here to give something back,” the former Ghana international said.
“I've been around a lot over the years and learned a lot, but all that, my whole career, I owe to this club. I have never forgotten that Hertha was always in my heart.”
Boating is currently a pundit on German public broadcaster ARD for the 2020 European Championships.