As an author, Herold primarily wrote French history books on Napoleon Bonaparte while also covering Joan of Arc and Madame de Staël.
He won the 1959 National Book Award for Nonfiction with Mistress to an Age: A Life of Madame de Staël and received a Guggenheim Fellowship in 1960.
After moving to New York in 1939, Herold went to Columbia University for a Bachelor of Science and a Master of Arts in the early 1940s.
[11] In 1958, Mistress to an Age: A Life of Madame de Staël received the gold medal for nonfiction as part of the California Book Awards.
[12] The following year, Mistress to an Age: A Life of Madame de Staël won the 1959 National Book Award for Nonfiction.