Glamorgan condemned Kent to another season in Division Two and avoided the ignominy of the wooden spoon after wrapping up a seven-wicket victory which promotes Derbyshire and Yorkshire.
In a match the Spitfires had to win to keep their promotion hopes alive, Rob Key's men spurned their chance as Glamorgan collected only their third win of the campaign late on day three.
Playing his last match for the Welsh county, veteran off-spinner Robert Croft fittingly claimed the final wicket of Kent's second innings, a scalp which set the home side a victory target of just 61.
Glamorgan lost three wickets in pursuit of the meagre target, but sealed victory late on the third day to ensure Derbyshire and Yorkshire claim promotion.
Kent resumed the third morning on 33-2 following on needing a further 187 to avoid an innings defeat.
A defiant 81 from Geraint Jones at least ensured Glamorgan had to bat again and, despite an early wobble, Ben Wright (15no) and David Lloyd (11no) carried their side home.
Robert Croft rolled back the years in his final first-class outing to leave Kent's promotion hopes in complete tatters at the Swalec Stadium.
The former England off-spinner claimed 5-31 as the visitors, replying to the Welsh county's first-innings total of 390, were shot out for 170 on day two.
Kent lost their last eight wickets for just 33 runs once Sam Northeast perished with a well-made 62, meaning they missed out on claiming crucial bonus points in the race to reach Division One.
Asked to follow-on, they lurched to 36-2, Rob Key and Daniel Bell-Drummond the men to go without troubling the scorers, by the close - they will return on Friday still needing a further 187 just to avoid an innings defeat.
Kent's frustrations had started in the morning session when centurion Jim Allenby and John Glover (55) added a further 46 runs in 10.4 overs.
Their stand of 128 was eventually ended by when Matt Coles had Glover caught at second slip. The same bowler also wrapped up the innings by removing Michael Reed, leaving Alleby unbeaten on 125.
Jim Allenby hit a century for Glamorgan to keep Kent's bid for promotion on hold after the first day of their LV= County Championship Division Two clash.
The Australian hit an unbeaten 100 from 132 balls, including an unbroken stand of 82 with John Glover for the ninth wicket, as Glamorgan ended the day on 334-8 at Cardiff.
Kent have to win the match if they are to have any chance of overtaking either Derbyshire or Yorkshire to claim one of the two promotion spots.
The hosts cruised to 133-2 from 31 overs before lunch as openers Will Bragg and Nick James looked comfortable in bat on a green-looking wicket.
However, in the afternoon Kent captain Rob Key looked far happier with his side as they made progress through bowlers Charlie Shreck and James Tredwell, who took four Glamorgan wickets between them.
After Graham Wagg was trapped lbw playing across the line to Matt Coles it brought Robert Croft to the wicket to warm applause in what is his final match for Glamorgan after 24 years with the club, although he was to last just six balls.
But his dismissal brought in Allenby and Glover and they frustrated the visitors, taking Glamorgan to a third batting point and then to the close.