Key – already on the pay-roll of the Zurich Premiership club as Head of Rugby Development – will share his responsibilities between the First Team and the club's academy set-up.
"For the last four or five years we've had a definite southern hemisphere influence at the club, from Bob Dwyer to Rod Kafer," Key told the Tigers website.
"We have gained a lot of experience as a result of their influence. I think that Dean [Richards] has now decided to look towards home grown coaches to bring on the English game.
"We are currently developing the style of the game. It's more of a 15-man game with hopefully more success allied to it. I felt that we became stale and potentially predictable last year in our approach and style of game and it was time for us to review and reflect on how we play. The new plan will allow us to be more successful and it's now time to implement it."
Key – who had two playing stints with the Midlands club, between 1975-81 and from 1987-92, will team up with head coach John Wells under Director of Rugby Dean Richards.