Green attended Columbia College, where he edited the Jester, starred in several Varsity Shows, and was a member of the Philolexian Society. He graduated from the college in 1942 and, after serving in the US Army in Europe during the Second World War, where he was also the editor of the army's Stars and Stripes newspaper, he returned to New York to attend the Columbia Journalism School.

Green wrote many novels, the best known being The Last Angry Man, published in 1956. It was adapted into a movie by the same name which was nominated for Academy Awards for Best Actor in a Leading Role (Paul Muni) and Best Art Direction-Set Decoration, Black-and-White. His other novels include His Majesty O'Keefe (co-authored with Lawrence Klingman), adapted into a 1954 film, North West, Portofino PTA, To Brooklyn With Love, My Son the Jock, The Lotus Eaters and East and West. His 1962 novel Portofino P.T.A. was adapted into a musical, Something More!, by composer Sammy Fain and lyricists Marilyn and Alan Bergman.

He wrote the teleplay for Holocaust, a critically acclaimed 1978 TV miniseries that won eight Emmy Awards, including one for "Outstanding Writing in a Drama Series," and was credited with persuading the West German government to repeal the statute of limitations on Nazi war crimes. He later adapted the script into a novel of the same title. In recognition for this effort, Green was awarded the Dag Hammarskjöld International Peace Prize for literature, 1979. Green won another Emmy nomination for his 1985 TV script for Wallenberg: A Hero's Story. Green was also a writer, producer, and director for NBC News. In 1952, he co-created (with Dave Garroway) NBC's The Today Show.

Green lived in Stamford, Connecticut for twenty years and moved to New Canaan, Connecticut. His first wife, Marie, died of cancer. They had three children: Nancy, Ted and David. He married Marlene Eagle in 1979, becoming stepfather to Dr Janie Worth (Née Eagle), Julie Cardo (Née Eagle) and David Eagle. Green died of pneumonia in Norwalk, Connecticut on August 29, 2006.