The win was sealed after their defense stopped Bama quarterback Ty Simpson short of the first-down marker, failing to convert on a fourth-and-long.
It is the first season-opening loss for Alabama since 2001.
Prior to the game, Florida State quarterback Tommy Castellanos made a confident remark saying, "They don't have Nick Saban to save them. I just don't see them stopping me." And right he was.
Castellanos posted 230 total yards (152 passing) and one rushing touchdown while completing nine of 14 passing attempts.
But it was the Seminoles rushing attack that showed out in the end - posting 230 yards and four touchdowns on 49 attempts.
After coming out of the half up 17-7, Florida State poured it on even more after running back Caziah Holmes punched it in to give his team a commanding 24-7 lead that Bama could never recover from.
Three straight quarters of being dominated wouldn't stop Bama from reminding themselves who they are. They cut the lead to just one score after a touchdown at the start of the fourth quarter.
Wide receiver Riley Scott made sure he got into the end zone by any means necessary to give the Crimson Tide a chance.
However, the Seminoles made sure to let Bama know whose house they were in.
Facing a 4th and 1 on their own 34-yard line, Florida State made the gutsy call to go for it - and converted. They eventually drove all the way down the field to put the game out of reach for good, thanks to a bouldering run from running back Gavin Sawchuk.
Florida State finished last year with just two wins. Now, it's looking like a brand new team, one that College GameDay legend Lee Corso was the only standalone analyst to pick the Seminoles over Bama during his final day on the job after 38 years.
Their next opponent is East Texas A&M on September 6th.
Meanwhile, Bama will return for their home opener on the same day to face UL Monroe.