While both bitter rivals came close in the first half through young prospects - James McAtee struck the post while Amad Diallo passed when he should have shot from a few yards out - there were no shots on target before the break, the first time since October 2016 where there were no such attempts in the first half of a Manchester derby.
A disallowed Bruno Fernandes stunner would ostensibly be the catalyst for a frenetic second half, where the ex-Sporting Lisbon man then teed up Alejandro Garnacho, whose low strike would seemingly prove decisive.
However, the birthday boy Bernardo Silva - celebrating turning 30 in the best way - met Oscar Bobb's cross on the stroke of full time to force penalties, although the Portuguese playmaker went first for the Premier League champions and was denied by Andre Onana.
An astounding Ederson stop from Jadon Sancho forced sudden death, though, and after a terrible effort from Jonny Evans, Manuel Akanji's final spot kick clipped the underside of the crossbar and ended Man City's Community Shield curse.
The Citizens had suffered three successive losses in the curtain-raiser before the 2024 edition - including in last year's clash with Arsenal - but thanks to a combination of Silva, Ederson and Evans, City hoisted the Community Shield aloft for the first time since 2019.
Birthday boy Bernardo saves City's bacon before Akanji penalty redemption
Offered a rest from the first whistle as McAtee pulled the strings in the number 10 role, Silva watched on helplessly as Pep Guardiola's side struggled to make their mark in the final third, although it was not for a lack of trying from their wide men.
Bobb in particular sought to attack the Man United backline at every opportunity, and just seven minutes after Garnacho's opener, the Norway international came up with a critical contribution, getting to the byline and chipping in a delicate dink to the back post.
Bobb's cross was on the money for Silva, who caught Facundo Pellistri unawares and easily out-muscled the Uruguayan winger before heading in past a stranded Onana, who could only watch Silva's effort ripple the top corner.
However, penalty role reversal saw Silva stand and watch the Cameroon international beat away his low effort, prolonging the Portuguese's 12-yard pain following his memorable failure against Real Madrid in the Champions League, but his spot-kick gaffe ultimately did not matter in the end.
Indeed, Swiss defender Manuel Akanji - who memorably missed the penalty that sent his nation crashing out of Euro 2024 in the quarter-finals to England - stepped up to the plate and exorcised that ghost with a terrific effort into the roof of the net, as Guardiola adds another winners' medal to his collection.
Alejandro Garnacho punishes Man City passiveness
For all of Man City's intricate build-up play and possession, Guardiola's side were otherwise found wanting in front of goal, as Onana received more than adequate protection from a patched-up Man United backline.
Casemiro rolled back the years in the Red Devils' midfield, while Fernandes was in the mood in the number 10 role and was responsible for the goal that sparked pandemonium from Wembley's red-clad end.
With eight minutes of normal time remaining, the Portuguese playmaker found Garnacho with a slick outside-of-the-boot pass, and his South American colleague took the game to the Citizens' backline, driving infield as Guardiola's men backed off.
Having been invited to shoot from 15 yards out, Garnacho accepted the offer and expertly found the far corner past Ederson's futile reach, although the smiles on Red Devils' faces were wiped out just a few moments later.
Marcus Rashford's goalscoring misery continues
Alongside Diallo and Mount's failed link-up in the first half, Marcus Rashford - who is aiming to banish a disappointing 2023-24 campaign to the past - was guilty of wasting a golden chance, opening up his body but curling wide from a promising area.
The England international was offered a gilt-edged opportunity to make up for that misdemeanour in the 75th minute, as Ten Hag's team turned defence into attack in the blink of an eye with a sizzling counter-attack, as Fernandes released Garnacho down the right.
The Argentine did what was required of him with a beautiful curling pass into the unmarked Rashford, and the whole of Wembley were seemingly just waiting for the net to bulge, but the 26-year-old inexplicably struck the outside of the post.
Replays showed that the ball struck Rashford's shin before clipping the frame of Ederson's goal, but regardless of which body part was involved, few could have foreseen the Englishman failing to find the target. On a day where he could have easily notched a brace for himself, Rashford departs with a familiar sense of attacking frustration, as his shooting boots continue to elude him.
What next for Man United and Man City?
Following their slog in the Community Shield, both Man United and Man City now switch their attention back to Premier League matters ahead of their first games of the 2024-25 season next weekend.
The Red Devils have the honour of playing in the campaign's inaugural match, away to Fulham on Friday night, two days before Guardiola's men start their title defence away to Chelsea.