As the film begins, saboteurs murder a U.S. worker on the highway and send his truck plunging down an embankment, making it look as if he were drunk.

MacWhite decides that the Freedom Road should be rerouted to a more provocative location, close to the border with North Sarkhan.

MacWhite and his wife travel to the countryside where they encounter Homer and Emma Atkins, a benevolent American couple running charity operations benefitting the people.

Rebel cadres led by Deong sabotage the Freedom Road opening, attended by Sarkhan's king and by MacWhite and his wife, causing a fiasco and casualties.

Parts of the film were also shot on locations in Bangkok, Thailand, including at Chulalongkorn University, one of the leading institutes of higher learning of the country.

The Ugly American received mixed reviews and was completely overwhelmed by a number of more popular films that year.

[8] The New York Times reported that Brando “moves through the whole picture with authority and intelligence,” and the New York Daily News said it was “one of Brando’s best performances.” But the negative view was reflected by the critic in Time who wrote that Brando “attempts an important voice but most of the time he sounds like a small boy in a bathtub imitating Winston Churchill” and called it a “lousy picture.”[9] Having analyzed six reviews written between 2003 and 2021, review aggregator Rotten Tomatoes categorized four of them as being positive, for an overall rating of 67% with a rating average of 6.1/10.

[10] Of twenty-three reviews examined by historian Jon Cowans, fourteen were positive, five negative, and four neutral or mixed.

Part of the problem is that producer-director George Englund, a friend of star Brando, isn't much of a director, and as a result the film is static and ponderous.

[11] Kukrit Pramoj, a Thai politician and scholar, was hired as a cultural expert/advisor to the film and later played the role of Sarkhan's Prime Minister "Kwen Sai".

Probably because of this, the word "Sarkhan" entered the Thai language as a nickname of Thailand itself, often with a slight self-deprecating or mocking tone.