Larsson was sent off by referee Craig Pawson after a foul on United's Ander Herrera late in the first half of the Premier League clash at the Stadium of Light on Sunday.
Struggling Sunderland, who lost to United 3-0, hoped to show that Larsson's challenge wasn't worthy of a red card, but Football Association chiefs have backed the dismissal.
“An Independent Regulatory Commission has rejected a wrongful dismissal claim from Sunderland's Sebastian Larsson,” an FA statement read.
“The midfielder was dismissed for serious foul play during the Black Cats' Premier League fixture against Manchester United on April 9th, 2017. Larsson's three-match suspension remains in place.”
Larsson will miss Sunderland's home games against West Ham United and Bournemouth either side of a trip to Middlesbrough before returning for the final four fixtures of the campaign.
His absence is another setback for Sunderland manager David Moyes, who insisted after the game that Larsson's tackle did not even warrant a yellow card.
Sunderland are 10 points adrift of safety after winning just one of their last 14 league games.