Yoro's capture continued the quick start United's new-look transfer department have made since INEOS took sporting control as they beat Real Madrid to the centre-back's signature.
Erik ten Hag has been keen to address last season's dismal Premier League finish and is being heavily backed in the transfer market with incomings and the shifting of players deemed not good enough.
The 18-year-old, described as a generational talent, was unveiled as United's newest addition on Thursday and reported for a first pre-season training session the next day as he met his team-mates for the first time.
Arriving at the club's Carrington headquarters on Friday morning, Yoro was greeted by midfielder Mason Mount as the pair headed indoors to report for duty.
New Manchester United signing Leny Yoro was straight to work after completing his £52m transfer from Lille
Walking out onto United's training pitch for the first time on an unusually hot Manchester morning, Yoro savoured the occasion while waiting for others to join him.
The defender - who will rival Harry Maguire for a starting place in Ten Hag's starting side - then took part in several training drills alongside his new colleagues.
Yoro showcased some quick footwork during a rondo passing drill that garnered shouts of praise from those alongside him who were seeing the star in action for the first time.
It is yet to be seen if Yoro will travel with United to Scotland for Saturday's pre-season friendly against Rangers at Murrayfield.
Speaking after completing his transfer to Old Trafford, Yoro said: 'Signing for a club with the stature and ambition of Manchester United so early in my career is an incredible honour.
'Since my first conversations with the club, they set out a clear plan for how I can develop in Manchester as part of this exciting project, and showed a lot of care for me and my family.
'I know about the history of young players at Manchester United and feel it can be the perfect place to reach my potential and achieve my ambitions, together with my new team-mates. I cannot wait to get started.'
He becomes United’s second signing of the summer after Bologna striker Joshua Zirkzee moved to Old Trafford for £36.5m.