Smith, who played 16 seasons in the league, was honored as the 2020 Comeback Player of the Year after returning to the field after suffering a devastating leg injury in 2018, which required 17 surgeries.
Smith, who will turn 37 in May, made the announcement on his Instagram in a heartwarming video.
“Two years ago I was stuck in a wheelchair, staring down at my mangled leg, wondering if I would ever be able to go on a walk again or play with my kids in the yard,” Smith said in the video. “On a routine play, I almost lost everything. But football wouldn’t let me give up. Because, no, this isn’t just a game. It’s not just what happens between those white lines on a Sunday afternoon.
“It’s about the challenges and the commitment they require. It’s about how hard and how far you can push yourself. It’s about the bond between those 53 guys in the locker room and everybody else in the organization. It’s about fully committing yourself to something bigger.”
Smith, who started six games for the Washington Football Team last year, led the team to a 5-1 record and the NFC East title. Their season came to an end in a 31-23 loss to Tom Brady and the Tampa Bay Buccaneers in the wild-card round of the playoffs.
“So, to everyone out there. Whether you’re a part of Niner Nation, the Chiefs Kingdom, or the burgundy and gold, I thank you,” Smith said. “To all the men who I had the privilege of standing with and playing alongside, thank you. I want to say thank you for believing in me, and thank you for helping me believe in myself.”
Smith, the No. 1 pick in the 2005 NFL Draft, finished his career with 35,650 passing yards, 199 touchdowns, and 109 interceptions. He was a three-time Pro Bowler while playing for the San Francisco 49ers, Kansas City Chiefs, and Washington Football Team.