After a disagreement with the board earlier in the season, differences were settled in order to see out the season, but the Austrian will now move on to pastures new.
What better way for him to cement his legacy than by bringing the Eagles their first-ever major European trophy just over a year after their FA Cup final victory over Man City, which got them into Europe in the first place.
Since then, the demotion from the Europa League to the Conference League, plus the losses of Eberechi Eze and Marc Guehi, had seen to it that the team from Selhurst Park endured the most tumultuous of seasons; however, the Conference League run has been their escape.
They faced a Rayo Vallecano side unbeaten in seven matches coming into Wednesday night's final, and playing a superb brand of passing football under their young 38-year-old coach Inigo Perez, who, like Glasner, was managing his last game for his club before moving on to coach Villarreal.
Last season's final saw a Premier League club from London, Chelsea, beat LaLiga's Real Betis. Was history going to repeat itself again?
Palace on the back foot in the opening exchanges
With an average age of 30.7 years in their starting XI, Rayo's team were that bit older than their opponents, who were boosted by the inclusion of Adam Wharton, returning after his recent injury.
That didn't stop the Lightning running rings around the Eagles in the opening exchanges, having a collective 70.2% possession in the first eight minutes.
When Palace did get forward, Florian Lejeune was consistently in the right place at the right time, as two clearances and an interception would attest.
Despite their manipulation of the ball for long periods, with 25 minutes gone, Rayo only had Alvaro Garcia's solitary touch in the Palace box to show for their efforts.
Eagles dangerman Ismaila Sarr fired off his 43rd shot of the competition - more than any other player - but his left-footed effort was quickly blocked.
Both Isi Palazon and Pathe Ciss were yellow-carded for tactical fouls within a few minutes of each other, and given that the former's natural game relies as much on his physicality as his ball-winning abilities, it meant Palazon would have to watch his step for the next 70+ minutes.
Alemao, with four goals in nine appearances in this season's Conference League campaign, was always going to be a handful for a Palace back four that was missing Chris Richards, and Rayo's No.9 almost scored the opener after a mistake from Chadi Riad.
Eagles begin to take control
With half an hour gone, Maxence Lacroix and Tyrick Mitchell still retained their 100% pass completion stat, as the Eagles looked to take control of the match.
Mitchell, as well as Daichi Kamada and Jaydee Canvot, had also each won two of their three one-on-ones, indicating a real desire on the part of the Premier League players.
The fact that neither keeper had had a save or a tackle to make, however, showed just how much of the game was being played in a congested midfield.
As half-time approached, Unai Lopez was a whisker away with a long-range effort, and Rayo's Jorge de Frutos was making his presence felt against what had become a five-man Palace defence.
At the other end, Andrei Ratiu's dithering almost cost his side a goal as his pocket was picked by Mitchell, who then saw a diving header from inside the six-yard box roll agonisingly wide, with Rayo custodian, Augusto Batalla, well beaten.
The same player had the first opportunity of the second half as Palace began on the front foot after the break.
Kamada certainly began to influence proceedings more, with 21 of his 25 passes finding their target, and 11 of them in the final third.
Mateta in the right place at the right time
When he wasn't keeping Pep Chavarria, Lejeune and Ciss on their heels, Wharton took the baton, and it was his fizzing shot that Batalla could only parry to Jean-Philippe Mateta, who steered the ball into an empty net.
Rayo's fifth goal conceded in the opening 15 minutes of a Conference League game really handed the initiative to Palace, and the Eagles began to flood forward at every opportunity, roared on by a fervent support.
Yeremy Pino's magnificent free-kick cannoned back off both posts, with the follow-up also hitting the woodwork, before Batalla's shin stopped Mateta from bagging his second.
In the space of 10 second-half minutes, Palace had tripled Rayo's shot output and shots on target, and had upped their percentage of successful dribbles to 40%.
Little threat from Rayo
As the hour mark approached, the Spaniards were right up against it, and needed Ratiu, Ciss and Lejeune to win three quarters of their aerial duels (three from four in each case).
That Rayo then began to hit consistent long balls told you everything you needed to know in terms of how much Inigo Perez had abandoned his side's normal way of playing.
Such a choice when De Frutos, for example, had won only one of his 10 duels, was misguided to put it politely.
The striker did eventually manage to sneak in behind and get a shot into the side netting, his first of any description on the night, and the ease with which he cut across Palace's back four to do so would've given Glasner some food for thought in the final stages of the game.
However, it was his final action of the game as he was subbed along with Alvaro Garcia, meaning that Rayo's two top scorers in 2025/26 (12 goals each) would play no further part.
The pace was still frenetic, with silly free-kicks being given away by both sides, and one of those gave Palazon the perfect opportunity to equalise with 15 to play.
His wild effort didn't trouble Dean Henderson, who had only had to make one save to that point, though to Rayo's credit, they came on strong in the final stages, upping the possession stats again to a collective 67%.
Without doubt, they were in the ascendancy, but they still had only managed one effort from Alemao on target.
The industry of Chadi Riad, Mitchell and Wharton, in particular, winning back possession on 13 separate occasions between them, continued to frustrate Rayo as time began to run out.
Still, the Lightning gave everything, and five shots after Sarr had had Palace's last attempt in the 64th minute meant that a tiring Eagles side really had to dig deep.
With two minutes left of injury time, Pedro Diaz tried to beat Henderson from way out when a number of his colleagues were better placed in the area. That told a story.
Europe League qualification Glasner's parting gift
A similar effort from Alemao was Rayo's last chance, and Palace's greatest-ever night soon became a reality.
Glasner's legacy, aside from landing another trophy for the club, will be that his side will contest Europa League football next season, 12 months on from when they were denied exactly that.
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