The Cameroon international has finally completed his prolonged move to Old Trafford following weeks of exit talks between the two Premier League clubs.
After three seasons and over 100 Seagulls appearances, Baleba penned an emotional goodbye to Brighton fans, as he joins Youri Tielemans and Andrey Santos as new midfield arrivals in Manchester.
The deal gives Brighton boss Fabian Hurzeler money to spend in the final days over the transfer window after the sixth first team exit this summer.
Jan Paul van Hecke's £52M move to Tottenham was the other eye-catching exit alongside departures for Carl Rushworth and Danny Welbeck.
Crucially, the call to sell Baleba also brings Brighton to a negative net spend on transfer fees for the first time since being promoted to the Premier League in 2017.
The latest figures reflect £790M spent on new players in that period, but with £813.1M brought in by sales.