On 19 March 2008, Cole was involved in a controversial incident in a Premier League game against Tottenham at White Hart Lane where he performed a high tackle on Tottenham's Alan Hutton.
Referee Mike Riley gave Cole a yellow card, a decision which was judged as too lenient by some analysts.
Chelsea were also fined £300,000 and Mourinho was fined £200,000, reduced on appeal in August 2005 to £75,000.
Negotiations continued throughout August and looked to be heading for deadlock, but eventually Cole signed for Chelsea on 31 August for a fee of £5 million, with William Gallas being transferred from Chelsea to Arsenal as part of the same deal.
The deal was closed after the transfer window had officially ended, and was not confirmed until an hour and a half after the deadline had passed.
Cole scored his first goal of the season in the seventh game in a tough trip to Manchester City in which he scored the opening and only goal to give Arsenal an important win.
He scored his second goal in a 3–1 away win to Aston Villa, scoring Arsenal's third in only the 28th minute.
Chelsea emerged victorious 1–0 after extra-time with a goal scored by Didier Drogba, to win the 2007 FA Cup.
Cole was reportedly one of the players upset when José Mourinho was relieved of his position as Chelsea manager.
In August 2006, after a protracted transfer saga, Cole completed a move to rival club Chelsea, with whom he won further honours, including the Premier League in the 2009–10 season, four FA Cups, one Football League Cup and one UEFA Champions League.
He was released by Chelsea at the end of the 2013–14 season.
Cole was given the number 3 shirt at Chelsea, and made his first appearance for the club as a substitute for Wayne Bridge in their 2–1 win over Charlton Athletic on 9 September.
He issued a public statement concerning his transfer saying he "forgave" Arsenal for how he felt he was treated during his time there.
At the age of 18, on 30 November 1999, he made his first team debut in the League Cup fourth round against Middlesbrough; Arsenal lost 1–3 on penalties after the match ended 2–2 at the end of extra time at the Riverside Stadium.