On March 4, 2009, Guerin was traded to the Pittsburgh Penguins in exchange for a conditional draft pick. The pick, a 2009 fourth-round pick if the Penguins made the playoffs, was later turned into a 2009 third-round pick once the Penguins advanced to the second round of the 2009 Stanley Cup playoffs. Guerin won the Stanley Cup on June 12, 2009, with the Penguins, defeating the Detroit Red Wings by a final score of 2–1 for Game 7 at Joe Louis Arena. His 14 years between Stanley Cups as a player was the third-longest wait in NHL history, behind Chris Chelios (16) and Mark Recchi (15).