He is considered by some to be the last american institutionalist. Others would consider him a Keynesian. I'd consider him sufficiently original and eclectic to warrant his own category. Galbraith was a member of a group that seems (to me) to have shrunk significantly in the past 20 years: academics who make a significant contribution to public life.
John Kenneth Galbraith, one of the most interesting economists of the second half of the 20th century, has died aged 97. Galbraith was a very good writer and a provocative social commentator.