The 33-year-old was due to stay at Northampton until the summer of 2022, but he will exit a year early to pursue a new opportunity, with the Hurricanes.
Franks arrived at Saints from another Super Rugby club, the Crusaders, back in 2019.
He teamed up with brother Ben at Franklin's Gardens and went on to play 24 times for the black, green and gold.
But Franks has not been able to cement a regular starting spot and he will not play for Saints again as he is sidelined with a foot injury sustained back in February.
He will move on from Saints this summer, and the double World Cup winner is looking forward to the next chapter in his career.
“It was an honour for me to pull on a Northampton jersey and to test myself at the very highest level of Northern Hemisphere rugby," Franks said.
“It has obviously been a challenging year in light of the pandemic, and also picking up a foot injury, but I thoroughly enjoyed my time as a Saint - particularly competing in Europe and getting the opportunity to play alongside my brother, Ben, one last time.
“I wish the club every success in the future but this is the right time for me to move on.”