What happened to him?
He had the best selling novel of 1991 in The Firm. And in 1993, the film adaptation of The Firm was the fourth highest-grossing movie of the year. Grisham fever seemed to sweep the nation, as more novels and more movies came out, all of them performing very well financially.
The Client, The Pelican Brief, The Rainmaker, A Time to Kill and so on. His books and the films they spawned were everywhere and were very popular.
But then around 2000 he just seemed to fade away.