Terms weren't disclosed but a league source told ESPN NFL Insider Adam Schefter that Campbell received a one-year deal.
The team announced the signing Thursday through its Twitter account.
- Cincinnati Bengals (@Bengals) March 20, 2014
Campbell will be reunited with Hue Jackson, his former coach with the Oakland Raiders. Jackson was promoted to offensive coordinator on Jan. 9 to replace Jay Gruden.
"Jason obviously has extensive playing and starting history, and as a backup [to Bengals starter Andy Dalton], he can provide the stability and experience we're looking for in that role," Bengals coach Marvin Lewis said in a statement.
"His experience will be a great asset to our other quarterbacks. He can play and win games for you if you need him. He's got great stature [6-foot-5, 230 pounds] and strength, the ability to stand in there under pressure and really throw the ball down the field."
The Browns released Campbell and Brandon Weeden on March 12. Campbell, in his only season with Cleveland, passed for 2,015 yards and 11 touchdowns with eight interceptions.