The Highlanders (7-4) trailed 33-29 before Shults scored on a 31-yard run with 1:50 to play.
Troy Arnold threw for 297 yards and four touchdowns for Johnson County (9-2), which saw Tyler Norris make 21 tackles — including four for a loss.
Arnold had touchdown passes of 87 yards to Nathan Lane, 70 yards to Corie Neely, 70 yards to Jared Kimble and 75 yards to Zack Eller. Lane scored on a 78-yard kickoff return for Johnson County’s other touchdown.
Pierce Hammonds scored on a 1-yard run for Gatlinburg’s first score and he caught a 24-yard pass from Shults for a 15-14 halftime lead.
Shults scored on a 30-yard run and Ethan Estabrook had a 29-yard interception return for the Highlanders’ other scores in the second half.
Oneida 23, Happy Valley 7
ONEIDA — The Indians scored 16 points in the final quarter to break a tie with the Warriors for the victory.
The Indians (8-3) scored first before the Warriors responded with a long touchdown throw from Dakota Cochran to Blake Young as the game remained tied at the end of the first, second and third quarters.
Happy Valley (5-6) was driving for the go-ahead score when a fumble in the red zone switched the momentum in Oneida’s favor.
Greeneville 54, East Hamilton 21
GREENEVILLE—Cade Ballard produced four total touchdowns and Jaevon Gillespie rushed for 143 yards for the Greene Devils (11-0), who led the Class 4A first-round game 34-0 at the end of the first quarter.
Recording two TDs in a 12-of-17, 167-yard passing performance, Ballard also ran for a pair of scores (53, 2 yards). Carrying the ball 11 times, Gillespie added two rushing touchdowns.
Dories Goddard totaled seven receptions for 123 yards and a TD.