Goals from Dan Burn and Alexander Isak were enough to secure the landmark victory for the Tyneside club against an unusually out-of-sorts Liverpool, who themselves were bidding for a record-extending 11th League Cup triumph.
Italian forward Federico Chiesa managed to claw one back in added time to add some late drama, although it was too little, and ultimately too late for the Reds.
The result also brought an end to Newcastle's torrid run of nine consecutive Wembley defeats and five final losses on the bounce.
'All for the fans'
Winning captain Bruno Guimarães was quick to dedicate the victory to a dedicated set of fans who have gone generations without a trophy.
"It's all for these fans," the Brazilian told Sky Sports.
"They deserve everything. When I first came here, I said I wanted to put my name in history.
"We can now say we are the champions again. This is one of the best days of my life.
"I don't have any words. It's the best day of my life. For them (the Newcastle fans) it's like the World Cup.
"People have grown up and not seen us as champions. My first year as captain of this club and it's one of the best days. This is unbelievable.
"This is my second home. We are making history. Some day when I leave this club I want the fans to sing my name the way they do to Shearer. He text me before the game. I'm so emotional today."
Meanwhile, Newcastle boss Eddie Howe vowed to enjoy the moment for once.
"We were well aware of the history and we wanted to do the club proud," Howe said after cementing his place in the club's history books.
"We wanted to score, we wanted to perform and we wanted to win.
"We are breaking new ground, I thought we were magnificent today.
"We worked consistently for two weeks on set plays just for this game and if you had seen us in practice you would have said we had no chance.
"We couldn't believe Dan Burn scored - he didn’t train like that! He was a colossus for us.
"I want to enjoy it first. I am always about tomorrow but I'll put the coaching books away for a few days."
"I've had worse weeks," goalscorer Burn added.
"I don't want to go to sleep because I feel like I'm dreaming and it's all going to be a lie.
"I feel sometimes I get around bodies and it's tough to get free.
"I feel strange, I feel numb at the minute."
Lessons learned
Pre-match, Eddie Howe referenced that changes had been made after lessons the Magpies took from their final two years ago, and they seemed to be working as his side started brightly, even if Harvey Barnes couldn’t guide his attempt from Jacob Murphy’s cross on target.
Murphy and Sandro Tonali were also unable to work Caoimhín Kelleher with their attempts, while a Liverpool side coming into this final off the back of a draining defeat to Paris Saint-Germain struggled to create despite having their fair share of possession.
Newcastle continued to be the main aggressors but Kelleher rushed out to deny Bruno Guimarães after Dan Burn had won the initial header from a corner.
Andrew Robertson made two vital blocks in quick succession to deny an Alexander Isak header and a Kieran Trippier strike, shortly before Kelleher held Guimarães’ flicked header following Burn’s first contact from the ensuing corner.
Burn rose highest to meet a corner delivery yet again moments before the break, but this time, Newcastle’s local boy went for goal and guided his superb header inside the far post to inspire rapturous celebrations in the black and white side of Wembley Stadium.
Another corner caused chaos for Liverpool soon after the break, but Isak’s goal was ruled out due to Guimarães being offside.
Undeterred, Newcastle’s talisman scored almost immediately after as Tino Livramento’s cross was nodded down by Murphy, allowing Isak to apply a clinical first-time finish.
Arne Slot responded with two alterations, one of which was Curtis Jones, who let off a venomous shot that Nick Pope tipped behind minutes later.
Kelleher then denied Isak’s improvised effort, Murphy placed his attempt marginally wide, and Tonali’s shot was saved as the unrelenting Magpies refused to let up, even with Slot making more attacking substitutions.
Eight minutes of added time being announced already had Newcastle fans worried, and any nerves were multiplied when Harvey Elliott slid in Federico Chiesa for the Italian to finish.
Despite that, and the fact the clock ticked past 100 minutes, the men in black and white hung on as Howe and his players wrote their name into Newcastle’s history books by ending the Magpies’ 70-year wait for a major domestic trophy, while also winning the club’s first-ever EFL Cup.
In contrast, Liverpool have lost back-to-back matches for the first time this campaign, with the terrible timing of that meaning the Reds miss out on adding to their 10 triumphs in this competition.
Flashscore Man of the Match: Dan Burn (Newcastle United)