Goals from Elliot Embleton and Ross Stewart were enough to hand Alex Neil’s side a memorable win in London.
Sunderland’s chairman was in attendance to witness the scenes with 50,000 supporters backing the Black Cats.
Sunderland announce young trio sign first deals with club
Sunderland transfer news: Former Black Cats star ‘open’ to SoL return this summer, Millwall ‘pull out’ of race to sign £2m Aberdeen ace
Newcastle United given green light to bid for winger
Arsenal negotiate 'significant sell-on fee' into defender's Sunderland contract
Sunderland AFC transfer rumours: Leeds United defender set for Championship move, Fabio Borini report plus Cats face competition for Jack Rudoni
Louis-Dreyfus was even spotted in Trafalgar Square ahead of the Black Cats’ League One play-off final against Wycombe Wanderers.
The businessman purchased 41 per cent of the club in 2021, with Juan Sartori, Charlie Methven and Stewart Donald owning the rest.
Posting on his personal Instagram, he said: “An unforgettable win at Wembley Stadium and our promotion back to the Championship - what a way to end our first season.
“I would like to thank all our fans around the world that have continued to support our club throughout what has been a difficult few years. Saturday was for you and together we achieved our goal.
“I commend our players and first-team staff for a great season and also thank all of our employees, who work so hard every day and give everything for the club. Without you, this success would not have been possible.
“I hope you all enjoy a fantastic summer and I look forward to seeing you back at the Stadium of Light for the start of our Championship journey.
“We will always keep going #TilTheEnd.