Grant last played in the NFL for the Giants in their 2011 Super Bowl success before being released by the franchise.
The 34-year-old former safety was not picked up by any other teams following an injury-plagued 2012 and has decided to retire as a Giant - a franchise with which he has a particularly strong affinity.
"I want to retire as a Giant because I want to be a Giant for the rest of my life," said Grant in a team release.
"The Giants are a connection in my heart that I knew that I was supposed to be there. The last year that I signed there to go to the Super Bowl, I could have signed with a bunch of teams, but I wanted to sign with the Giants.
"The way that the owners opened the doors and signed me back and the general manager [Jerry Reese] and the coaching staff, we did each other a favour, but it definitely solidified my career for me."
Grant also enjoyed spells at the Carolina Panthers, Jacksonville Jaguars and Seattle Seahawks during his 11-year career.