A prolific writer on musical subjects, he was particularly known for his biographies of the bel canto opera composers Rossini, Donizetti, and Bellini which he published between 1963 and 1971.

Weinstock was born in Milwaukee, Wisconsin but from 1930 was based in New York City where he became the music editor of the Alfred A. Knopf publishing house in 1943.

[3][4][5] Weinstock became the music editor for Alfred A. Knopf in 1943 and remained associated with that publishing house for the remainder of his career, apart from a period between 1959 and 1963 when he worked for Doubleday and Macmillan.

It was followed by Handel (1946), Chopin: The Man and His Music (1949), Donizetti and the World of Opera in Italy, Paris and Vienna in the first half of the Nineteenth Century (1963) and Rossini (1968).

[8] In addition to his books and translations, Weinstock was a music critic for The Saturday Review, The New York Times, and from 1966 for the British journal Opera.