He will now take up the role of national creative director at Ambience Publicis in Mumbai. The position has been vacant since the departure of Pushpinder Singh in October 2005.
In a statement, Prasoon Joshi, the regional creative director at McCann, said: "Shastry's exit is a loss for McCann. He was one of the best creative minds we had. But then, each one of us has our own personal, as well as professional, preferences and needs to move on in life."