George Maharis was a close contender for the role of Pardner.
Jean Seberg's singing voice was dubbed by Anita Gordon, while Clint Eastwood and Lee Marvin did their own singing. Marvin's recording of the song "Wanderin' Star" went to #1 on the British charts, earning him a gold record.
This film version bears little resemblance to the Broadway musical on which it is ostensibly based. After the success of several musical films in the 1960s, most notably The Sound of Music (1965), producers went looking for other projects to make, and "Paint Your Wagon" made the list. The original plot, about an inter-ethnic love story, was discarded as being too dated. The only elements retained from the original were the title, Gold Rush setting and about half of the songs.
Lee Marvin was set to star in The Wild Bunch (1969), a project that he helped put together with stuntman Roy N. Sickner, when Paramount offered him $1 million plus a percentage to star in this picture.
The play was produced on Broadway in 1951 and was one of the two properties Louis B. Mayer took with him after being ousted from MGM. Advancing age and the fact that Mayer had been so removed from actual film production for 30+ years rendered him unable to get it underway as a film.
Although a musical, no choreographer was ever hired.
Paint Your Wagon opened at the Shubert Theater on November 12, 1951 and ran for 289 performances.
Only one number is sung by a trained singer - "They Call the Wind Maria" by Harve Presnell. (The word "Maria", spelled Maria without the H, is sung/pronounced as "Mariah".)
Lee Marvin had to be made to look older in the movie, since at 44 he was only six years older than Clint Eastwood.
Lee Marvin was apparently drunk nearly every day of filming.