The 26-year-old Wales international has extended his stay at the King Power Stadium until 2018.
King spent two years in Leicester's youth academy before penning his first professional contract with the Foxes in 2006.
"I'm absolutely buzzing. To have come so far with the club and to be playing in the Premier League now is a dream come true," he told Leicester's official website. "To be able to commit my future and for the club to have shown this sort of faith in me is a massive boost so I'm just looking to kick on now.
"I've only ever played for Leicester City and it's looking more and more like they're the only team I'll ever play for. I would love it if that is the case."
King has made seven appearances in all competitions for Leicester so far this season.