Kuechly released a video announcing his decision.
"I think now is the right chance for me to move on," Kuechly said in the video message. "It makes me sad because I love playing this game, I've played it since I was a kid. It's my favorite thing in the world to do. The memories I have from this place and this organization and being on the field with these guys, they'll never go away."
"Beyond his extraordinary performance on the field, Luke has had a tremendous impact on this organization and region," Panthers owner David Tepper said of Kuechly. "In my two seasons with Luke, I quickly recognized how special of a person he is. The respect he gives and garners from others as well as the positive impact he has on his peers is second to none. It's obviously going to be very difficult for all of us because we know that no player can replace what he's been for this organization for the last eight years. His presence can't be replicated." He went on to call Kuechly "a once-in-a-generation player and someone we want every member of this organization to emulate."
While he doesn't explicitly say it, the numerous concussions that Kuechly sustained throughout his career probably played an important part in his decision to call it quits. In 2015, the seven-time Pro Bowler missed three games when he remained in concussion protocol for 34 days.
The following year, Kuechly suffered another concussion with the searing image being him crying as he was taken off the field on a cart.
Kuechly ended up sitting out the final six games of the season. Despite that heartbreaking sight of a tearful Kuechly, he continued playing, and in 2017, he was placed on concussion protocol for the third time in as many years.
Kuechly has managed to play every single game the last two seasons.
Scroll down to read reactions to Kuechly's surprising announcement below.
This post will be updated.