The 28-year-old was placed on the free transfer list by Newcastle earlier this month after criticising the club via Twitter for their lack of ambition in the transfer market.
Alan Pardew had previously stated he intended to keep Barton at St James' Park despite the bust-up, but hinted the midfielder needed to 'buy into what the club are doing'.
But having completed his switch to Loftus Road, Barton has revealed the first impressions at the club were a factor in his decision, as well as their ambition in the transfer market.
"The ambition of the club really impressed me," Barton told the club's official website.
"There's obviously a great set of lads here already and that's why they had such a great season in the Championship.
"The gaffer [Warnock] is talking about adding two or three more bodies and that, combined with the potential of the Club and the new owners' ambitions, bodes really well for the future."
QPR boss Neil Warnock was delighted by the capture of Barton, his first signing since Tony Fernandes' takeover of the club last week, and has dismissed the midfielder's negative reputation as a result of his previous outbursts.
"We've got a very, very good player on our hands," said Warnock.
"He's coming here to show people what he can do. He wants to get back into the England team.
"He's very enthusiastic. People will say one or two things about him, but they've said stuff about me in the past too, so I won't worry about that.
"He's a winner. Even without the armband on, he's a captain every week.
"He's a lot better play than people give him credit for. Hopefully we can harness all his positive characteristics and get the best out of him.
"I think with Tony's backing and Amit coming back on board this is a really positive step for the football club."
Newcastle United's managing director, Derek Llambias said: "On behalf of everyone at Newcastle United we wish to thank Joey for his on field contributions to the team and we wish him every success for his future at Queens Park Rangers."