The 33-year-old signed for the Italian champions on July 10 for a fee understood to be £105m. It ends his nine-year stay at Real Madrid.
Ronaldo, who requested the transfer from Real Madrid, confirmed Juventus’ reported £30m-a-year offer was his only one during this summer transfer window.
“Usually players of my age go to Qatar or China, with all due respect, so coming to such an important and outstanding club at this point of my career makes me very happy,” Ronaldo said.
He completed a medical in Turin on Monday, where 5,000 shopkeepers in the north-western Italian city have put up posters that read “Bem-vindo!” – welcome in Portuguese.
The five-time Ballon d’Or winner arrives at Juventus on the back of four Champions League titles in five years with Real Madrid, but he has targeted more trophies at the Italian club.
“I’d like to mark the history of Juventus,” said Ronaldo, who has 73m Twitter followers compared to the club’s 6m.
The Portugal captain insisted he will not turn his back on his national team and said joining Juventus is “not a holiday”.
“I’m very well physically, mentally and emotionally so that’s why I’m so proud of being here and of the way I came here,” he said. “It gives me so much motivation for the future.
“I’m different from all the other players that think their career is over at my age.
“I really want to show I’m not like the others, I’m different, it’s a very emotional moment for me and the club because I’m not 23, I’m 33.”
He added: “The age is not important, I feel good, I feel motivated, excited.”
Juventus’ squad have begun pre-season training but Ronaldo said he will join up with them on July 30 and aims to play in their first competitive game of the 2018-19 campaign.
Ronaldo insisted winning a sixth Ballon d’Or, which would take him beyond Lionel Messi’s haul, was not a part of his decision.
“I always want to win and be the best,” he said. “If things were to go well, I might have the chance to win it, but it is not something that I lose sleep over.”