Layton, who was originally from Hudson, lost a fight with cancer in August 2011 at the age of 61.
Current NDP Leader Tom Mulcair and Layton's family members, including his widow Olivia Chow, attended the renaming ceremony at what used to be known as the Hudson Marina.
"Jack Layton spent a huge amount of time learning how to swim, how to sail, and what a perfect place to be," said Chow. "It's about families, and families having the time and facilities to enjoy each other's company."
"When you've spent years with Jack, you know how much sun there was in his life," Mulcair said. "Jack was about enjoying life, he brought a very positive message of hope and a sunny day like this in a park on Quebec's national holiday is a way to bring all that together."
The park is located on the shore of Lake of Two Mountains.