The veteran winger agreed to a US$3-million, two-year deal on Tuesday.
Dupuis was eligible to become an unrestricted free agent on July 1.
He's spent parts of the last four seasons with the Penguins and won a Stanley Cup with the team in 2009.
The 32-year-old had 17 goals and 37 points in 81 games last season.
In 668 career NHL games with Pittsburgh, Minnesota, Atlanta and the Rangers, he has 130 goals and 277 points.