Short answers, pulled from the story.
Carl Foreman wrote the screenplay for High Noon based on a four-page plot outline he created. He purchased the film rights to John W. Cunningham's 1947 short story The Tin Star and developed it into the final script.
High Noon was filmed during late summer and early fall of 1951 across several locations in California. Scenes appeared at Iverson Movie Ranch near Los Angeles, Columbia State Historic Park near Sonora, and the old Sierra Railroad in Jamestown.
Carl Foreman left the United States because he faced blacklisting after refusing to name names before the House Un-American Activities Committee in 1951. Production partner Stanley Kramer demanded immediate dissolution of their partnership and Harry Cohn pressured him out of Hollywood.
The song Do Not Forsake Me Oh My Darling won an Academy Award for Best Original Song with music by Dimitri Tiomkin and lyrics by Ned Washington. It became a major hit on country-and-western charts for Tex Ritter and later as a pop hit for Frankie Laine.
John Wayne refused the lead role in High Noon because he believed the story was an allegory against blacklisting. He later told an interviewer that he never regretted helping run Carl Foreman out of the country.