Amid confusion and without clear orders from above, Jäger made the snap decision to open the barrier at Bornholmer Strasse - but the former guard, now 71, refuses to take credit.
"It's not me who opened the Wall. It's the East German citizens who gathered that evening," Jäger said. "The only thing I can be credited with is that it happened without any blood being spilled."
The protest movement in East Germany (the GDR) had been snowballing for weeks and border guards were on alert. But Jäger said that nothing on the day of November 9th suggested history would be made that night.
'Choked on my roll'
At 7pm, Jäger had been watching a press conference where East German official Günter Schabowski, announced the relaxation of travel restrictions to the West.
"I almost choked on my roll," he said.” I didn't believe my ears and said to myself: 'What stupidity has just been announced?'"
The lieutenant colonel, who was attached to the Stasi secret police, had worked for the East German border police for 28 years, and was the deputy chief at the Bornholmer crossing in the north of East Berlin.
He had anticipated a normal shift, taking over responsibility for 14 officers from 6.00pm local time, when his boss went home.
At the canteen, however, where Jäger was eating supper, things quickly changed when he watched the TV coverage of Schabowski's unexpected announcement. The East German authorities did not seem to expect the waves of people waiting to be let through the Wall.
'Let us leave!'
Standing at his post, Jäger was soon overwhelmed by the growing crowd. Repeated back and forth calls with his superiors to ask advice on what to do with the swelling crowd yielded little.
"You're calling because of such a stupid thing?" his boss grumbled down the line, instructing Jäger to simply send the citizens home if they did not have the necessary travel authorization to cross the border.
But people began shouting, “let us leave!".
In a panic, Jäger rang his boss back. But he recalls being told by his superior: "I have no order from above. I have no instructions to give you."
The crowd kept swelling and by around 9.00 pm, the access road to the border crossing was blocked by the mass of people.
Jäger picked up the phone again and shouted down the line: "We have to do something!"
Jäger then received orders to identify the most agitated members of the crowd and let them alone cross into the West, in the hope that this would calm the mass of people.
"But that had the opposite effect. The crowd became increasingly agitated," Jäger said, recalling his fear of a stampede in which citizens would be crushed.
"That's when I said to myself: 'Now it's for you to act. Whatever happens, we have to let the East German citizens cross the border'," he said.
'Open the barrier!'
At around 11.30pm, he finally decided to take matters into his own hands.
"Open the barrier!”, he shouted.
Initially, his 14 men stood glued to the spot, dumbfounded, and so he repeated his instruction.
At dawn on November 10th, when his shift finally ended, Jäger rang his sister.
"It's me who opened the border last night," he told her.
"You did well," she replied.
Even 25 years on, recounting the tale from the sofa in his small two-room apartment in a village north of Berlin, he becomes emotional as he remembers the white and red barrier being opened.
"I had never seen such euphoria, and I've never seen it since," Jäger said, smiling.
SEE ALSO: The Local's Berlin Wall series