Walter Piston descended on his father's side from Antonio Pistone, his grandfather, who sailed from Italy and settled in Rockland, Maine. Here the family, to seem more American, dropped the final 'e' from their name. Walter Hamor Piston, Jr., was born in Rockland on 20 January 1894, where he lived until he was ten and then moved to Boston. After serving the US Navy in World War I he entered Harvard University, graduating summa cum laude in 1924. He then spent two years in Europe from 1924-26 on a John Knowles Paine Traveling Fellowship, and studied composition with Paul Dukas at the Ecole normale de musique, and also took private lessons from Nadia Boulanger. From 1926 until his retirement in 1960 Walter Piston was a member of the faculty of Harvard University, where he was (from 1951) Walter W. Naumburg Professor of Music. His students agreed that Piston brought together to the classroom musical scholarship, humanity, wit, and empathy, making him one of the most significant musical educators of his time. He received the Pulitzer Prize in 1948 and in 1961, and was three-time winner of the New York Music Critics Circle Award. He wrote four books on the technical aspects of music which are considered to be classics in their fields - Principles of Harmonic Analysis (1933); Harmony (1944); Counterpoint (1947); and Orchestration (1955).

Few American composers have composed so extensively and yet with such uniform excellence. His work habits were remarkably methodical; he rarely altered or revised his music once it was put on paper, and his handwriting was calligraphic. With two exceptions, he never wrote for voices.

Piston died in Belmont, Massachusetts in 1976. Today, he is best known for his ballet The Incredible Flutist, his two violin concertos, eight symphonies, and numerous wonderful chamber works.