His parents were the American Jewish screenwriters Frank Davis and Tess Slesinger,[3] and after his mother's death in 1945, Isabelle Fair Wrangell became his stepmother.

His mother was active in politics with the American Communist Party: a Stalinist, she signed a letter denouncing the Dewey Commission's investigation of the Moscow Trials.

From 1961 to 1964, he worked on FDR, a 26-part television series for which he interviewed President Roosevelt's family, friends, enemies, Cabinet members and political associates.

In 1965, Davis moved to CBS News as a writer and worked on documentaries about student rebellion, homosexuality, slavery, the Six Day War, racism and hunger in America.

[5] Davis' Hearts and Minds, a film about American military action in Vietnam, won the Academy Award for Best Feature Documentary for the year 1974.