A degenerative knee injury has forced Essendon hard-nut Devon Smith to retire from the AFL, aged just 29.

Injury-hit Essendon best-and-fairest Devon Smith has retired from the AFL, aged 29.

Smith has brought his 182-game career to a close, informing Bombers teammates on Friday morning.

After 109 games with GWS as an inaugural player at the AFL's 18th club, Smith moved to Essendon at the end of 2017.

The forward-midfielder proved to be an instant success at Tullamarine, collecting the Bombers' Crichton Medal in his first season at the club.

But a degenerative knee injury has restricted him to just eight AFL games this season.

"While it wasn't an easy decision to come to, unfortunately I couldn't quite get the body to where it needed to be to perform week-in and week-out," Smith said.

"I've loved my AFL journey and I've had the true privilege of representing two fantastic football clubs.

"I want to thank all my past and present teammates for all their support across the journey.

"As players, your time in the AFL goes by so quickly and my message to them this morning was that they shouldn't lose sight of the fact it is a privilege to run out with your best mates every week."

Essendon football manager Josh Mahoney acknowledged Smith's service to the red and black over the past five seasons and was sad to see him retire prematurely.

"Despite his body letting him down at times with his injuries, Devon was always hungry to get the best out of himself," Mahoney said.

"He was an ultimate competitor and was selfless in his role when the side required it.

"Devon added immense tackling pressure and his ability to hit the scoreboard always strengthened our side when he was at his prime."