Chiang was born in 1967 in Port Jefferson, New York. Both of his parents were born in China and emigrated to Taiwan with their families during the Chinese Communist Revolution before emigrating to the United States. His Chinese name is Chiang Feng-nan (). He graduated from Brown University with a computer science degree. He had been submitting stories to magazines since high school and after attending the Clarion Writers Workshop in 1989 he sold his first story, "The Tower of Babylon", to the Omni science magazine.