Blake Szymanski, who was expected to start at quarterback, did not play after missing significant practice time this week because of a bruised shoulder. He got hurt last week in relief of Griffin, who is expected to miss most of the season with an isolated tear to the ACL of his right knee.
Florence was 20-of-27 passing for 216 yards and added 60 yards rushing. He gave Baylor (3-1) the lead for good with a 6-yard touchdown run in the second quarter.
Jacquise Terry had 109 yards rushing for Kent State (2-3), including a 61-yard scoring run in the third.
Baylor's Kendall Wright caught nine passes for 125 yards, and Jarred Salubi rushed for 64 yards and a touchdown in support of the freshman Florence.
Griffin, who passed for 2,091 yards and 15 touchdowns as a freshman in 2008, spent the first half on the sidelines wearing a headset. During pregame warmups, Griffin gingerly walked around while encouraging some of his teammates and even lobbed a couple of soft tosses while playing catch in the end zone.
The star quarterback wasn't the only offensive starter in street clothes for Baylor. Starting running back Jay Finley missed his second straight game with an ankle injury.
Even with most of its starting backfield missing, the Bears had 374 yards of offense.
Florence capped an 89-yard drive with a 6-yard run that finished by diving into the end zone. This gave the Bears a 14-7 lead with 13:02 left in the first half.
The score came three plays after he hit Wright on a screen pass, which the speedy receiver turned into a 44-yard gain.
Salubi's 45-yard touchdown run gave the Bears a 21-7 halftime lead. Then Florence showed off his athletic ability on the opening drive of the second half.
Florence scampered for gains of 14 and 10 before his 29-yard scoring run gave the Bears a 21-point lead.
Terry, who had his second straight 100-yard game, brought Kent State within 28-13 with his touchdown.
The Golden Flashes drove deep into Bears territory three times after that but only scored a safety. Freddy Cortez missed a field goal and Kent State was stopped twice on fourth-down attempts inside the 10, including once on a fake field goal.
Kent State has lost all three of its games this season to schools from BCS conferences. In those setbacks, the Golden Flashes have turned the ball over 10 times and committed 25 penalties, including 11 Saturday night.
Playing for the first time in Texas, Kent State scored on the game's opening drive.
Quarterback Giorgio Morgan fired a lateral to receiver Leneric Muldrow, who connected with a wide open Jameson Konz for a 35-yard touchdown pass. It was the first time this season the Golden Flashes scored on their opening drive.
Baylor came right back, tying the game at 7-7 on the ensuing possession.
Florence kept the drive alive by hooking up with Ernest Smith for 10 yards on third-and-7, then Salubi broke loose for a 28-yard run down to the Kent State 2.
Two plays later, Jarod Monk scored on a 1-yard run.