Behind Zow, the Crimson Tide (4-5, 3-4 Southeastern Conference) snapped a three-game losing skid, while the Bulldogs (2-6, 1-5) will have their first losing season since 1996.
Both teams used backup quarterbacks most of the way.
Zow, who entered after Watts pulled a groin muscle in the first quarter, led the Tide to all 24 points. He tied the game with a 9-yard TD pass to fullback Donnie Lowe early in the fourth after Alabama had given up 17 straight points.
Santonio Beard darted 14 yards for his second touchdown with 5:44 left for the game-winner. He had 15 carries for 95 yards, including a 6-yard score in the first half.
It was a nice way for the seniors to go out at home.
"There's 22 guys out there that played their last game at Bryant-Denny," Franchione said. "It's good for them to go out on a win.
"I'm happy for the team. We needed something like this."
After Lowe's score, Alabama got the ball back on its own 49 after Jared Cook's 18-yard punt. The normally slow-footed Zow ran for 8 yards on fourth-and-1 to keep the drive alive. Three plays later, Beard took the pitch and raced untouched along the left sideline for the winner.
Alabama's defense made the lead stand. The Tide had given up 1,146 yards passing in the past three games and blown a series of fourth-quarter leads.
Mississippi State got one first down on three possessions in the final quarter.
"It's a game we felt we needed," said defensive end Kindal Moorehead, whose return from an injury rejuvenated the pass rush. "We really needed to show we can come through in the end."
Added defensive tackle Jarret Johnson: "We won it the way people said we couldn't. That's why we're so excited about this game."
Kevin Fant, who replaced a struggling Wayne Madkin in the second quarter, couldn't engineer his second straight comeback win.
Punter Lane Bearden put the Bulldogs at their own 4-yard line with 2:17 left. The Tide had lined up for a 54-yard Neal Thomas field-goal attempt but took a delay of game penalty and punted.
He moved the ball 17 yards on three short completions, setting up a fourth-and-7. Saleem Rasheed batted away a pass across the middle, and Zow was able to run the clock out.
"This was a good win for Alabama because they are struggling like we are," said Mississippi State coach Jackie Sherrill, a former Tide player. "Alabama played better than we did in the fourth quarter on both sides of the ball."
And it affected the Bulldogs' confidence.
"There were times in the second half when we needed a big play and did not get one and people let things get them down," Fant said.
Reduced to a backup role coming into his senior season, Zow finished 12-of-22 for 157 yards and now stands 17 yards shy of Jay Barker's career school passing mark of 5,689 yards.
He admitted to coming out "anxious, jittery, nervous" but settled down in the second half.
"They team believed in me. They kept me up on the sidelines," Zow said.
Fant replaced a struggling Wayne Madkin late in the first half and completed 17 of 29 passes for 175 yards and a pair of scores.
His 9-yard TD pass to Justin Jenkins with 1:24 left in the third quarter gave the Bulldogs a 17-10 lead.
Madkin was just 2-of-8 for 8 yards with an interception. Fant had led the Bulldogs back against Kentucky in their last game.
The Tide weren't celebrating long, with Auburn awaiting next week.
"It's over. We celebrated in the locker room and now it's time for Auburn," Johnson said.