Smallwood (6-2, 225) originally signed with the Kansas City Chiefs as an undrafted rookie free agent on May 8, 2018. He was waived by the Chiefs on May 16, later re-signed with the team on May 30 and was waived on September 1.

A 23-year-old native of Jenks, OK, Smallwood attended the University of Oklahoma. In five years with the Sooners (2013-17), he played in 47 games (two starts) and tallied 18 receptions for 170 yards and one touchdown. As a senior in 2017, he appeared in 14 games (one start) and finished with 10 receptions for 97 yards and one touchdown and earned the team's Don Key Award, the highest honor an OU football player can receive while playing for the Sooners, which goes to the player who best exemplifies the superior qualities of Key, both on the field and in the classroom.