A central midfielder in his playing days with 14 national team caps, Amorim took charge of Primeira Liga side Sporting in 2020.
He won the league in his first full season in 2020-21, ending Sporting’s league title draught of 19 years, before repeating the success last campaign.
After replacing Erik ten Hag, Amorim signed a contract until June 2027 with United, his first match set to be against Ipswich Town on November 24.
Amorim signed off as Sporting manager with a 4-2 comeback victory against Braga, making it 11 wins in as many games in the league this season.