Pietersen was frozen out of the international picture in August last year when he was dropped for the final Test against South Africa over claims he sent text messages to rival players criticising then-England captain Andrew Strauss.
The South Africa-born batsman subsequently returned to the squad towards the end of 2012, but was only tied to a short-term contract that was due to expire at the end of the month.
However, limited-overs coach Ashley Giles confirmed on Wednesday the 32-year-old has now signed a full central contract with the ECB that puts him on a par with the rest of his England teammates.
The current set of central contracts is due to expire at the end of September.
Pietersen endured a turbulent 2012, which saw him announce his retirement from both 50-over and Twenty20 internationals.
He even cast doubt over his future in the Test arena, shortly before he was axed from the side in August over a controversial exchange of text messages with the touring South Africa team.
He missed the World Twenty20 in Sri Lanka and was not given one of 10 central contracts distributed in September.
However, after holding talks with the ECB he returned to the England squad in October and subsequently agreed to return in all formats of the game.