Born in Newton, Massachusetts to a literary family, he was the son of Gertrude Darling and Robert Benchley (1889-1945), the noted American writer, humorist, critic, actor, and one of the founders of the Algonquin Round Table in New York City.

Nathaniel Benchley was the highly-respected author of many children's/juvenile books that provided learning for the youthful readers with stories of various animals or through the book's historical settings. Benchley dealt with diverse locales and topics such as "Bright Candles", which recounts the experiences of a 16-year-old Danish boy during the German occupation of his country in World War II; and "Small Wolf", a story about a Native American boy who meets white men on the island of Manhattan and learns that their ideas about land are different from those of his own peoples'.

Film director/producer, Norman Jewison made Benchley's 1961 novel The Off-Islanders into a motion picture titled The Russians Are Coming, the Russians Are Coming for which he received the nomination for an Academy Award for Writing Adapted Screenplay. He was a close friend of actor Humphrey Bogart and wrote his biography in 1975.

Benchley's novel Welcome to Xanadu was made into the 1975 motion picture Sweet Hostage.

His elder son, Peter Benchley (1940-2006), was a writer best known for writing the novel Jaws and the screenplay of the 1975 Steven Spielberg film made from it. His younger son, Nat Benchley, is a writer and actor who has portrayed his grandfather, Robert Benchley, in a one-man, semi-biographical stage show, "Benchley Despite Himself". The show was a compilation of Robert Benchley's best monologues, short films, radio rantings and pithy pieces as recalled, edited, and acted by his grandson Nat, and combined with family reminiscences and friends' perspectives."

Nathaniel Benchley died in 1981 in Boston, Massachusetts and was interred in the family plot at Prospect Hill Cemetery in Nantucket.

(as written in Wikipedia - free online reference service)