Director Martin Ritt was forever known after this movie as the man who tamed Orson Welles. During filming Ritt drove Welles into the middle of a swamp, kicked him out of the car and forced him to find his own way back.
During post-production, Martin Ritt found that it was nearly impossible to understand any of Orson Welles' dialogue. He and his team worked overtime to improve what they could through post-dubbing. Some cast members thought that Welles had done it quite deliberately as a way to show contempt for the "mumbling" method actors of the Actors Studio, but no one could ever be sure.
Angela Lansbury relished her role and thoroughly enjoyed working with director Martin Ritt - "He had a wonderful enthusiasm and earthy sexy quality himself. He loved the idea of the dirtiness of the carryings on, and he certainly brought every bit of kind of naughty sexuality out of me in that role."
Orson Welles had a rough time making the film and caused plenty of trouble. Used to being in control of his own projects, it was hard for him to do things someone else's way. According to Angela Lansbury, "He was always nudging and pushing for things and wanted to change lines, but had to be carefully handled so that he didn't always get his way because his way wasn't necessarily the best way for everybody else in the scene." Welles would irritate his co-stars by overlapping his own lines with their dialogue, ad-libbing, and mumbling to the point where his lines were barely comprehensible. "There was something you couldn't resist about Orson," said Lansbury, "even though he was a son-of-a-bitch at times. I mean, there's no question about it, he was very difficult." Joanne Woodward added in a 2001 interview, "Orson had a hard time. It must have been a terrible, terrible feeling for him to be confronted by all these young hot shots who thought they were so great because they came from New York and the Actors Studio. It was a problem."
The scorching Louisiana heat didn't help Orson Welles' temperament on the set. "He was having terrible difficulty living in his own skin," said Angela Lansbury. "He was very very heavy. We were working under dreadful conditions of heat and he was perspiring and he seemed to have a lot of very thick makeup on." Part of that heavy makeup was a prosthetic nose that Welles wore - something he often did for his acting roles. The heat made Welles sweat so much that his fake nose would often come unglued and ruin the shot.
Orson Welles was 42 years old, but was cast as a 61 year old man due to his weight. He had already played a similar older fat man the year before in Moby Dick and the following year in his Touch of Evil.
Paul Newman and Joanne Woodward channelled their off-screen chemistry into their characters and worked beautifully together. "They seemed to have such a total understanding of each other," said co-star Angela Lansbury in a 2001 interview, "that they were able to work in scenes where they were at each other's throats or falling under each other's spell."
Oscar Levant said about Producer Jerry Wald, "He suddenly became involved with William Faulkner. He'd buy a Faulkner property and that turgid, incomprehensible prose was on one occasion transformed into " The Long, Hot Summer." In that picture Orson Welles played a "big daddy" type of role. Sometimes he was inaudible - Those were his best moments."
The title song for the series, "The Long, Hot Summer" (performed by Jimmie Rodgers and written by Sammy Cahn and Alex North) was also used as the title song in the 1965 TV series of the same name featuring Roy Thinnes and Nancy Malone.