Johnson, 5-10, 175 pounds, was signed by the Falcons as a college free agent out of Southern Methodist following the 2013 NFL Draft. He led the Falcons with 13 catches for 158 yards and one touchdown during the preseason. Johnson was named the MVP in back-to-back bowl games for the SMU Mustangs, including the 2011 BVAA Compass Bowl after posting seven catches for 120 yards with one touchdown in a win over Pittsburgh.