The young United star has also been joined in celebration by his twin brother Romario who has also signed a one-year pro deal at Elland Road.
Ronaldo, 18, signed his first professional contract back in April, two days before making his Whites debut in the season finale at Preston North End.
The teenager made an immediate impression and after becoming a regular component of head coach Garry Monk’s first-team squad, the midfielder has signed fresh terms at Leeds until the summer of 2019.
Vieira could now face competition from his twin brother who plays in the same position and has signed his first professional deal at the same time.
Romario will initially join United’s Development Squad at Thorp Arch and will eventually look to follow his twin brother into Monk’s first team.
“Me and my brother have played together for most of our lives,” said Ronaldo.
“I’m happy to be sharing the same club with him again and I’m happy he’s been given the opportunity.
“He’ll keep working hard like he does in every training session on and off the pitch.
“Hopefully he’ll be able to break into the first team and carry on from there.”
Reflecting on his own rapid rate of progress, Ronaldo added: “It feels great to have managed this within less than a year of first coming to the club, especially because it’s a club like Leeds.”
Romario beamed: “I’m delighted to sign my first professional contract with Leeds United.”
“Having my brother here makes it even better – he’s doing well and has made a good start. It’s our hometown club.
“We could probably play next to each other or fight for the same position – it depends what the gaffer wants.
“I like to work hard on and off the ball. I try to keep things simple and always do my best on the pitch.
“I want to keep working hard and, eventually, I hope to push towards the first team.”
Romario’s signature adds yet another potential option in midfield for Monk’s men who brought in Bournemouth midfielder Eunan O’Kane as the club’s sole recruit on Wednesday’s transfer deadline day.
There were no departures.
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