He played college football for the Florida Gators and was selected by the Cleveland Browns in the fourth round of the 2018 NFL draft.

[17][18] Callaway began training camp competing against Jeff Janis, Ricardo Louis, and Rashard Higgins for the job as the fourth wide receiver on the Browns' depth chart.

[19] Callaway and Rashard Higgins became contenders for a starting wide receiver position after Corey Coleman was granted a trade request on August 5, 2018.

[20] Head coach Hue Jackson named Callaway the third wide receiver on the depth chart to start the regular season, behind Jarvis Landry and Josh Gordon.

He made his professional regular season debut in the Browns' season-opener against the Pittsburgh Steelers and returned a kick for an eight-yard gain during their 21–21 tie.

[21] On September 16, 2018, Callaway earned his first career start and replaced Josh Gordon due to a hamstring injury.

[22] Callaway caught his first career touchdown reception on a 47-yard pass by Browns' quarterback Tyrod Taylor during the fourth quarter.

[23] The following day, head coach Hue Jackson named Callaway the starting wide receiver after the Browns traded Josh Gordon to the New England Patriots.

[24] In Week 8, Callaway made a season-high five receptions for 36-yards and caught a one-yard touchdown pass thrown by Baker Mayfield as the Browns lost 33–18 at the Steelers.

[25] On August 9, 2019, Callaway was suspended for the first four games of the 2019 season for violating the NFL's substance abuse policy.

[44] On August 5, 2018, Callaway was issued a citation in Strongsville, Ohio for possession of marijuana and driving with a suspended license during a traffic stop at 3am.