"A.J. is one of the best receivers in the NFL," Bengals head coach Zac Taylor said. "He's an important part of our plans, and we're thrilled to have him in the fold from Day 1. We're looking forward to the impact of his talent and leadership on our offense this season."
Green said the decision is part of his long-term plan to finish his career in Cincinnati.
"Play another four years and I hope to retire as a Bengal," he told Geoff Hobson of the team's official website.
Green quickly emerged as one of the league's top playmakers after the Bengals selected him with the fourth overall pick in the 2011 draft. He earned Pro Bowl selections in each of his first seven years and was named Second Team All-Pro three times over that span.
The 31-year-old University of Georgia product has missed significant time with injuries over the past two years, though. He was limited to nine appearances in 2018 because of a toe injury and missed the entire 2019 campaign after suffering an ankle injury in training camp.
"It's a process of trying to be great. You play this game long enough, you're going to have these bumps in the road and you have to keep fighting. That's where I am," Green told Hobson in May. "Still fighting. I still love the game. I'm just ready to get back and play."
Getting him back on the field will be critical this season after the Bengals invested the first overall pick in the 2020 draft on Joe Burrow, who's coming off winning the Heisman Trophy and leading LSU to a national championship in his final collegiate season.
Green, Tyler Boyd, John Ross III and Auden Tate give Cincinnati one of the league's deepest receiving groups if the team's top target can stay healthy this season.
Add in running back Joe Mixon and the Bengals have the potential to make a massive jump after ranking 26th in total offense last year.
Green, Burrow and Co. are scheduled to open the regular season Sept. 13 against the Los Angeles Chargers.