The 26 year old has never really settled and City is his 8th club since starting with Arsenal in 2000. In that time he's started just 110 league games, scoring 34 goals but he wants consistency and he has a chance to get it under Dave Jones.
"I'm really excited about coming to Cardiff," he said. "This is a great club with superb fans and huge ambition.
"Of course I've got something to prove. Maybe there are a few people out there who doubt me, but I'm going to quieten them down.
"I don't really want to be talking about what I can and can't do - I'd rather let my football do the talking."
Bothroyd is likely to feature today against Southampton but maybe from the bench. He only joined City on Monday and Jones may opt for the double Scotch pairing of McCormack and Thompson upfront.
But Jones has told Boothroyd what he expects of him amd the club.
"He told me how he wants the club to move forward and what he expects from me," Bothroyd continued.
"And now I feel like I'm ready to keep my head down, work hard and produce my best football for a few years.
"We can certainly challenge for promotion. There are a lot of talented players and the manager knows the way he wants to play.
"Look at the FA Cup run last year. They beat a Premier League side and they've been unbeaten in pre-season against some quality sides - so why can't we got ahead and take that into the Championship?
"You want a good start, but if you don't, there are lots of games where you can catch up.
"If you'd have asked anyone, they wouldn't have said Stoke and Hull would get promoted last year, but they came through and managed it."