 He was a graduate of the State University of New York at Oneonta and the University of Iowa.Called "the Stephen Crane of World War II" by Kurt Vonnegut, MacMillan was the recipient of a number of literary awards, including the Hawaii Award for Literature in 1992, the O. Henry Award, the Elliot Cades Award for Literature in 2007, and the Pushcart Prize.He was further honored in 2010 by the creation of the Ian MacMillan Writing Awards in his memory at the University of Hawaii.