Smith, 25 of Birmingham, Ala., was arrested at a security checkpoint at Hartsfield Jackson International Airport when crews found a .38-caliber handgun in his carry-on bag, said Atlanta police Sgt. Greg Lyon.
Smith was charged with carrying a weapon in an unauthorized location of the airport and was taken to the Clayton County Jail in Jonesboro - about 20 miles south of Atlanta. He posted $3,000 bond Friday, according to court records. The records didn't indicate if the gun was loaded.
Smith made his initial court appearance Friday morning and is scheduled for a preliminary hearing on Feb. 4.
Bengals spokesman Jack Brennan said franchise officials will not comment on ongoing legal matters, and a call to Smith's attorney was not immediately returned.
Smith was a first-round draft pick in 2009 out of Alabama.