Reports had suggested the 19-year-old striker could be set to leave Stamford Bridge at the end of the season after talks that began in September failed to reach an agreement over a contract extension.
But the Frenchman, who joined Chelsea in 2007 after a legal wrangle with former club Lens, ended speculation about his future by agreeing to a new deal which will now run out in 2015.
"Since I signed for Chelsea when I was 16 all I was thinking about was to get to the first team," said Kakuta, who has made nine appearances for the club this season.
"Now I have been playing a few times with the first team and I have signed for four-and-a-half more years, I have to make a way for myself into the starting 11 and make my dream come true.
"The manager said to me it is the right time to play and I think for me it is as well. It's my job to do my best and try to play more often and show the coach that I am good enough to play in the team."