"Carlos Fernandes, Jorge Vital, Adélio Cândido, Emanuel Ferro and Paulo Barreira have transferred from Sporting to United with our new coach, who started work in Manchester earlier this week," the Red Devils announced on their website.
The quintet joins a team that already includes first-team coaches Darren Fletcher and Andreas Georgson, as well as assistant goalkeeping coach Craig Mawson.
According to United, Carlos Fernandes, 29, will be Amorim's "right-hand man", as he was at Sporting and his previous clubs (SC Braga and Casa Pia).
Jorge Vital will be the head goalkeeping coach, Adélio Cândido - the only one waiting for his work visa - will be his assistant, as will Emanuel Ferro, who worked with Amorim between 2006 and 2009 at Benfica, when Amorim was still a player, and rejoined the now coach at Sporting, where he stayed for nine years before moving to England.
For his part, Paulo Barreira will be the fitness coach at the Manchester club, having already worked at Arsenal and Liverpool, as well as in Saudi Arabia and the United Arab Emirates, before joining Amorim's team at Sporting in 2020.
Amorim headed to what is considered the most important football league in the world after just seven seasons as a coach, a career that began at Casa Pia and included a spell at SC Braga, before arriving at the lions in 2019/20 in exchange for the 10 million euros of the termination clause.
Two league titles (2020/21 and 2023/24), three League Cups (2019/20, for SC Braga, 2020/21 and 2021/22) and a Cândido Oliveira Super Cup (2021/22) were enough to convince Manchester United, 20 times English champions and three times winners of the Champions League.
The former player is also the second Portuguese to manage the Red Devils, after José Mourinho (2016-2018), in a spell that featured a Europa League win, at a club looking to return to the top after Alex Ferguson's historic 27-year legacy.
Manchester United, where Portuguese internationals Diogo Dalot and Bruno Fernandes play, are 13th in the Premier League, 13 points behind Liverpool, who are top of the table after 11 matches.