Rush was born in San Francisco and raised in Oakland, the son of Roger and Leslie (Chesse) Rush. He graduated from Swarthmore College in 1956.[3] During the Korean War, he was sentenced to two years incarceration for his status as a conscientious objector to the war, but was released on parole after nine months. After working for fifteen years as a book dealer, he changed careers to become a teacher and found he had more time to write. He submitted a short story about his teaching experiences to The New Yorker, which was published in 1978.
Rush and his wife Elsa were co-directors of the Peace Corps in Botswana from 1978 to 1983, which provided material for his short story collection Whites (1986). Whites was a finalist for the 1987 Pulitzer Prize for Fiction.[4] His Botswana experience also served as the setting for his novels Mating (1991) and Mortals (2003).