A header by Casemiro followed by an own goal by Sven Botman late in the first half silenced the hordes of Newcastle fans who flocked to the capital as United went on to lift the trophy for a sixth time with relative ease.
While much of the build-up was about Newcastle's first appearance in a major final since 1999, it was Erik ten Hag's resurgent United who claimed the club's first silverware since winning the Europa League under Jose Mourinho in 2017.
There was little between the sides in a scrappy first half but the English season's first silverware was effectively decided in the space of six minutes towards halftime.
Newcastle were stunned when Brazilian Casemiro met a superb Luke Shaw free kick in the 33rd minute to head past Loris Karius, the goal allowed to stand after a VAR check for offside.
Six minutes later Newcastle were left totally deflated when the in-form Marcus Rashford was played in down the left and his shot deflected over a helpless Karius, the goal later being credited to the unfortunate Botman.
Kicking towards their fans in the second half Newcastle roused themselves into action and pinned a leggy-looking United back at times but their wait for a trophy goes on.
Newcastle's fans, who had created a sea of black and white with give-away plastic flags at the stadium's west side during the closing minutes, drifted away before the presentation.
The Tyneside club has now lost each of their last nine matches at Wembley, a run that began in the 1974 FA Cup final.
By contrast Man United's fans were in full voice as Bruno Fernandes raised the trophy which they hope will be the first of many under Dutch coach Ten Hag whose first season is going from strength to strength after some difficult early days.
United, who beat Barcelona in midweek to reach the last-16 of the Europa League and are still in contention in the Premier League title race, were not at their best.
But they had far more goal threat and Wout Weghorst fluffed a chance when he shot tamely at Karius, Newcastle's third-choice keeper playing his first competitive match since 2021.
Newcastle looked dangerous occasionally when Allan Saint-Maximin got on the ball but their lack of goals in recent months was evident as they huffed an puffed.
Joelinton headed one chance over and Dan Burn's header whistled wide on the stroke of halftime but by that stage the writing was on the wall for a familiar near miss for Newcastle.