Michael Chopra said he is sorry to leave Cardiff but the former Newcastle striker admits the Premiership lure to join Sunderland was too strong.
Michael Chopra is delighted to be returning to the Premiership
On Friday the Black Cats completed a deal worth up to £5m to sign the 23-year-old on a four-year deal.
"I am sad to leave," Chopra told the Cardiff website. "It's been a pleasure and the fans have been fantastic to me.
"But I have to do what's best for my career and my dream was always to get back into the Premiership."
Chopra arrived at Ninian Park in June 2006 from Newcastle in search of first-team football, although the Magpies were reluctant to let the striker go.
The ex-England youth international had been with his hometown club since 2002 but wasted no time in establishing himself in south Wales, scoring 22 league goals last season in the Championship.
It's a good deal for all parties
"When I first came to the club I didn't really know the city or the other players apart from Stephen McPhail, but now I love the city and I love the club," Chopra said.
"I've got to pay tribute to the manager, Dave Jones, because he took a gamble on spending £500,000 on me and hopefully that gamble has paid off."
A 10-fold profit on their original investment is good business for Cardiff, for whom money has been tight due to previous debts and £43m earmarked for the development of a new 25,000-seater stadium.
Manager Jones admits he would have preferred to keep his top scorer, but could not stand in Chopra's way once Sunderland's bid activated a £5m release clause in the player's contract.
"We did put a clause in his contract and if clubs met that then they were entitled to speak to him," Jones said.
"The decision was still Michael's, but he has an opportunity to play Premiership football earlier than he thought he might have.
"You can't turn that opportunity down and the money that we've got maybe enables us to step up another gear quicker in other areas.
"It's a good deal for all parties, although one or two of the fans might not be happy that we're selling."