The 22-year-old put pen to paper on a six-year deal with United, keeping the frontman at St. James' Park until the summer of 2025.
Joelinton will wear the famous number nine shirt and could be in line to make his United debut in Saturday's pre-season friendly at Preston North End.
Joelinton told nufc.co.uk: "I'm really happy to be here. I know the club is investing a lot in me and it's a huge responsibility. But I'm happy, motivated and I hope to give something back on the pitch.
"I know it's a big club, with massive history here in England and around the world. I've followed the Premier League from Brazil since I was little and know about the huge tradition of the club and how passionate the fans are.
"I'm passionate about the game. I bring a lot of emotion on to the pitch. I'll never being lacking in desire and dedication. I like playing football and like to enjoy myself on the pitch.
"I hope to have a great career here. As I said before I'm really happy and hope to bring a lot of joy to the fans and everybody involved with the football club."
Joelinton will aim to follow in the prestigious footsteps of Alan Shearer, Les Ferdinand and Andy Cole, three strikers who heavily excelled on Tyneside whilst wearing the famous number nine jersey.
And, along with becoming Newcastle's record signing, Joelinton is ready to prove his worth for the Magpies and make a positive impression on his new club.
The Brazilian added: "I know it's a huge responsibility; the great Alan Shearer, the team's biggest idol. I know it's a big responsibility but I'm prepared. I know that everyone at the club has faith in me having brought me here.
"I hope to contribute on the pitch. Rest assured there'll be no shortage of desire and dedication to score lots of goals and honour the number nine shirt.
"It brings a lot of responsibility knowing that it's the club's record transfer, knowing that they're placing a lot in faith in me. But I'm relaxed, I know my quality and I'm prepared. It gives me a lot of motivation to honour this shirt, give my best on the pitch and help my team-mates.
"I think a lot about the team, looking to help out my team-mates and score goals, which is the most important thing. I look to improve every day. Physically, I'm in great shape, I've got good physical strength. I train hard.
"These are my main characteristics. I'm a good dribbler and passer of the ball and I hope to show that on the pitch."
