Answer by taking a quote from the following article:

Dimitri Zinovievich Tiomkin (May 10, 1894 - November 11, 1979) was a Russian-born American film composer and conductor. Classically trained in St. Petersburg, Russia before the Bolshevik Revolution, he moved to Berlin and then New York City after the Russian Revolution. In 1929, after the stock market crash, he moved to Hollywood, where he became best known for his scores for Western films, including Duel in the Sun, Red River, High Noon, The Big Sky, Gunfight at the O.K. Corral, and Last Train from Gun Hill. Tiomkin received twenty-two Academy Award nominations and won four Oscars, three for Best Original Score for High Noon, The High and the Mighty, and The Old Man and the Sea, and one for Best Original Song for "The Ballad of High Noon" from the former film.

Following his work for Fred Zinnemann on The Men (1950), Tiomkin composed the score for the same director's High Noon (1952). His theme song was "Do Not Forsake Me, Oh My Darlin'" ("The Ballad of High Noon"). At its opening preview to the press, the film, which starred Gary Cooper and Grace Kelly, did badly. Tiomkin writes that "film experts agreed that the picture was a flat failure... The producers hesitated to release the picture." Tiomkin bought the rights to the song and released it as a single for the popular music market, with singer Frankie Laine. The record became an immediate success worldwide. Based on the song's popularity, the studio released the film four months later, with the words sung by country western star Tex Ritter. The film received seven Academy Award nominations and won four awards, including two for Tiomkin: Best Original Music and Best Song. Walt Disney presented him with both awards that evening.  According to film historian Arthur R. Jarvis, Jr., the score "has been credited with saving the movie." Another music expert, Mervyn Cooke, agrees, adding that "the song's spectacular success was partly responsible for changing the course of film-music history". Tiomkin was the second composer to receive two Oscars (score and song) for the same dramatic film. (The first was Leigh Harline, who won Best Original Score for Disney's Pinocchio and Best Song for "When You Wish Upon a Star". Ned Washington wrote its lyrics as he did for "Do Not Forsake Me, Oh My Darlin".)  The song's lyrics briefly tell High Noon's entire story arc, a tale of cowardice and conformity in a small Western town. Tiomkin composed his entire score around this single western-style ballad. He also eliminated violins from the ensemble. He added a subtle harmonica in the background, to give the film a "rustic, deglamorized sound that suits the anti-heroic sentiments" expressed by the story.  According to Russian film historian Harlow Robinson, building the score around a single folk tune was typical of many Russian classical composers. Robinson adds that the source of Tiomkin's score, if indeed folk, has not been proven. However, the Encyclopedia of Modern Jewish Culture, on page 124, states: "The fifty-year period in the USA between 1914, the start of the First World War and the year of Irving Berlin's first full score, Watch Your Step, and 1964, the premiere of Boek and Hamick's Fiddler on the Roof, is informed by a rich musical legacy from Yiddish folk tunes (for example Mark Warshavsky's "Di milners trem," The miller's tears: and Dimitri Tiomkin's "Do Not Forsake Me." High Noon)..." The composer worked again for Zinnemann on The Sundowners (1960).  Tiomkin won two more Oscars in subsequent years: for The High and the Mighty (1954), directed by William A. Wellman, and featuring John Wayne; and The Old Man and the Sea (1958), adapted from an Ernest Hemingway novel. During the 1955 ceremonies, Tiomkin thanked all of the earlier composers who had influenced him, including Beethoven, Tchaikovsky, Rimsky-Korsakov, and other names from the European classical tradition.

what was special about high noon?
"film experts agreed that the picture was a flat failure... The producers hesitated to release the picture.