James Whitmore is the only actor to receive an Academy Award nomination for a film with a cast of just one person.
In addition to Who's Afraid of Virginia Woolf? (1966) and Sleuth (1972), this is only one of three films in which entire on-screen billed cast received acting Oscar nominations. Sleuth (1972)'s credits, however, did include several nonexistent actors to mislead the audience into thinking it was not just a two-character thriller whilst Who's Afraid of Virginia Woolf? (1966) did feature two uncredited bit players as roadhouse employees, neither of whom were obviously Oscar nominated.
The film is "one of only two films for which every member of the cast was nominated for the Best Actor Oscar (the other was Sleuth (1972))" according to the TCMDb (Turner Classic Movies).
The film and source stage play's title, "Give 'em Hell, Harry!", is a phrase associated with U.S. President Harry S. Truman. The Wikipedia website states: "The title comes from an incident that took place during the 1948 Presidential election campaign. In Bremerton, Washington, Truman delivered a speech attacking the Republicans. During the speech a supporter yelled out "Give 'em Hell, Harry!". Truman replied, "I don't give them Hell. I just tell the truth about them and they think it's Hell"."
First Oscar nomination in around twenty-six years for actor James Whitmore for this film. Whitmore was Oscar nominated for Best Actor in a Leading Role for this movie and had previously been Oscar nominated for Best Actor in a Supporting Role for Battleground (1949). On neither occasion did Whitmore win.