Cardiff, who have agonisingly missed out in the play-offs for the last three seasons, will play in the top flight next season for the first time since 1962.
Their promotion was greeted with joyous scenes at the final whistle with players and fans celebrating on the pitch.
"There are a lot of smiley happy faces and it's going to be a long night in Cardiff I think," manager Malky Mackay told Sky Sports against a deafening noise at the Cardiff City stadium.
"I'm delighted for these people. There are a lot of people here who have gone through a lot of hard times and this is for them," added the Scotsman who took over the team in 2011.
"The staff of the football club, the back office, the training ground staff, the directors and our owners, these players and these fans and the people of Cardiff, it's a night for them," added the former Watford boss.
"I am lost for words right now. We thoroughly deserve that if I'm honest," Cardiff defender Mark Hudson told the BBC.
"The consistency we've had this year, top since November, and now we're promoted. We'll celebrate now then go for that title."
At the other end of the table, Bristol City's six seasons in the Championship ended when a 1-0 defeat at home to Birmingham City consigned them to relegation to League One.
As well as missing out on promotion through their play-off heartache, they were beaten in the FA Cup final in 2008 and by Liverpool in last season's League Cup final on penalties.
