He has played nearly 250 times for Hearts and moves South after over a decade with the Edinburgh club.
Pearson told the club's official website: "We are absolutely delighted to have secured Robbie for the football club.
"He will bring quality, experience and a winning mentality, all of which we have no doubt will enhance our squad for the season ahead.
"On meeting with Robbie, his leadership qualities were obvious. We are continuing our policy of only signing players who genuinely want to play for Leicester, and Robbie certainly fits that criteria."