The decision to recall the South African-born batsman was made after he met coach Andy Flower, captain Alastair Cook and other senior players and members of England's management team this week.
"We were keen Kevin should hold a series of face-to-face meetings with team management and senior players before the Test squad departs for the UAE and India next week," England and Wales Cricket Board managing director Hugh Morris said in a statement.
"The meetings were constructive and cordial and all outstanding issues have been resolved.
"All the England players and management are now keen to draw a line under this matter and fully focus on the cricketing challenge that lies ahead in India."
Pietersen, 32, who averages 49.48 from 88 Tests, was dropped for the third and final Test against South Africa at Lord's in August after admitting sending provocative texts to the opposing players.
But he denied allegations he had told them how to dismiss former captain Andrew Strauss, who retired from all cricket after South Africa won the Test series 2-0.
Pietersen used his Twitter account to express his delight at being back in the England squad.
"The happiest days of my career have been playing cricket for England," Pietersen said. "Long may that continue!"
ECB national selector Geoff Miller said it would be good to have an extra batsman in the squad, especially as Ian Bell was due to return home for the birth of his child midway through the tour of India.
"We are pleased to welcome a player of Kevin's proven international calibre back into the squad for such an important Test series," said Miller.
"As we anticipate Ian Bell will return home for the birth of his first child around the time of the second Test in Mumbai, the team will benefit from having an extra batsman in the squad."