Clark Gable did not get along with director John Ford during filming, and at one point walked off the set in protest at Ford's treatment of Ava Gardner. Ford also made several remarks about Gable's age and weathered appearance.
Clark Gable and Grace Kelly began an affair on the set that lasted for several months. After filming had ended, they resumed the affair while Kelly was filming The Country Girl (1954). Despite this story, Kelly biographer James Spada insists that, although Kelly was infatuated with Gable, he did not want to get involved with a woman 30 years his junior. Although he liked her, Spada claims, theirs was a father-daughter relationship. However, Donald Sinden has said that Gable and Kelly did have an affair during filming.
Maureen O'Hara was the first choice for Honey Bear Kelly, but MGM needed Ava Gardner in a movie and made John Ford cast Gardner instead, which is one of the reasons for Ford's vicious treatment towards Gardner while filming.
Donald Sinden (and all male members of the crew who removed their shirts) had to shave any hair from their chests daily, as Clark Gable (who did not have a hairy chest) thought it an affront to his 'manliness'.
Although the original trailer for the film explains that "Mogambo" means "the Greatest," in fact, the word "Mogambo" has no meaning at all. Producer Sam Zimbalist came up with the title by altering the name of the Mocambo, a famous Hollywood nightclub.
During the London shoot, Clark Gable took a room in an out-of-the-way hotel so he and Grace Kelly could continue their relationship discreetly. Unfortunately, this was also when the affair ended. Kelly's mother came to stay with her in London, and her apparent approval of the relationship and hopes that the two would marry scared Gable off. He stopped returning Kelly's phone calls and avoided her on the set. When the distraught actress went to Ava Gardner for advice, her co-star counselled "He likes to conquer, and when he's done, he's through with them, and he leaves them"
Clark Gable got sick on location. A gum infection forced him to return to Los Angeles, mainly because he insisted on seeing his own dentist. When he returned to the set, Frank Sinatra brought with him spaghetti, tomato sauce and other Italian foods. He and Ava Gardner prepared a massive feast for the entire company. Years later, John Ford would say the dinner was the condition he set for allowing Sinatra to come along on the shoot.
Ava Gardner was pregnant at the start of filming, and as her pregnancy progressed she began to suffer greatly from the heat. Finally, she took a break in England, where she wound up in the hospital. Publicity flacks, who had not released news of her pregnancy, said she was suffering from anemia. A few years later she would say that she had suffered a miscarriage, but in private she told the wife of cinematographer Robert Surtees that she had had an abortion. At that point in her relationship with Frank Sinatra, she hated him so much she did not want to bear his child.
Ava Gardner arrived in Africa for location shooting with current husband Frank Sinatra in tow. Their marriage was on the rocks at the time following a huge bust-up during a house party at which Lana Turner was a guest. Some reports claim Sinatra found the two women in bed together. More likely, he caught them giggling over the sexual prowess of musician Artie Shaw, to whom both women had been married (Sinatra was jealous of all of his wife's previous romances). At first he canceled his plans to accompany her to Africa. When Gardner changed her phone number, he proposed a reconciliation in Earl Wilson's gossip column. They spent most of their time on location fighting and making up, both at top volume.
Ava Gardner had barely met John Ford before filming started. On location, she was upset that he didn't treat her as a star and wasn't giving her much direction. Finally, she turned away from him in anger while shooting a scene. He pulled her aside and told her "You're damned good. Just take it easy." From then on, they got along fine.
While Ava Gardner was shooting a scene with a baby elephant, the creature pushed her into a mud pool. She screamed for help, but John Ford motioned the crew to keep quiet and keep on filming. The scene proved to be one of the funniest in the movie.
The lead role was originally intended for Stewart Granger, but MGM decided to employ Clark Gable instead. Production chief Dore Schary suggested to Granger that the film would entail a long separation from his wife Jean Simmons, though Granger wanted to make the film regardless and later spoke disparagingly about Gable in his memoirs.
The censors in Spain did not allow adultery to be shown on the screen. For that reason, MGM changed the relationship of the characters of Linda Nordley (Grace Kelly) and Donald Nordley (Donald Sinden) from wife and husband to sister and brother in the dubbed version released in Spain. However, they did not delete a scene in which both share a bed together.
During the filming, Frank Sinatra had caught word of Columbia Pictures' plans to film From Here to Eternity (1953) and launched a campaign to win the plum supporting role of Maggio. He got Ava Gardner to call studio head Harry Cohn, a friend of hers, and intercede for him. He was in Africa when Cohn demanded a screen test. Gable loaned him the money to return to the states. Sinatra won the role - which would win him an Oscar® and trigger one of the biggest comebacks in film history - and returned to the location for a much happier visit with his wife.
During filming in Kenya, MGM hired armed guards to protect the cast and crew in the event of an attack by Mau Mau terrorists. It was rumored that the studio made a secret payment of $50,000 to Mau Mau leader Jomo Kenyatta to protect the cast and crew. Nonetheless, all involved in the filming were issued weapons with which to protect themselves.
Years of heavy drinking had left Clark Gable with a case of the shakes. John Ford, who suffered from the same problem, was sympathetic and tried to shoot around Gable's bouts of palsy. When the schedule got tight, however, he refused to re-take a scene between Gable and Ava Gardner. This led to a rift between the two. Though they were able to finish filming without any more problems, Gable would never work with the director again.
To get to the film's African locations, Clark Gable was forced to fly for the first time since the death of his wife Carole Lombard in a plane crash. The flight hit a storm with rock-sized hailstones and had to make a forced landing in the jungle. That near-disaster actually reawakened his interest in flying.
Always an avid sportsman, Clark Gable spent breaks in filming hunting in the wild. He was delighted to learn that co-star Grace Kelly enjoyed hunting, too. As they went off together, the two developed a romance. Kelly started calling him "ba," the Swahili word for "father," which was close to "Pa," Lombard's nickname for him. Kelly would later admit to going skinny-dipping with him. Donald Sinden later told interviewers he had caught Gable and Kelly in bed together.
The crew created an 1800-yard airstrip in the jungle so they could fly in mail, food and medical supplies from Nairobi and fly out each day's rushes. The camp was first set up in Tanganyika, then reassembled in Uganda.
Some episodes in the film were based on events that happened during the shoot. Just as in the movie, a leopard actually wandered into Ava Gardner's tent one night. She also took a stab at cooking for the entire crew, just as her character does on screen.
Christmas fell during the shooting schedule. At the company's celebration, Frank Sinatra and the natives sang Christmas songs, and John Ford read "'Twas the Night Before Christmas." Among Sinatra's presents to Ava Gardner was a shower unit he set up with one of the production's carpenters.
Hundreds of native tribesmen were flown in to appear in the film, including some from tribes that were traditional enemies. The entourage included 68 members of the Wagenia tribe, hired to film a boat trip through the rapids. When they decided their gods were not present on the river, producer Sam Zimbalist flew in three chiefs from Leopoldville to bless the sequence.
To shoot the rhinoceros attack on the car, hunter Frank "Bunny" Allen drove the camera car so he could keep an eye on the animal. When two other rhinos appeared from the bush and charged the camera car, Allen and cinematographer Robert Surtees were sent flying 100 feet - in the jeep. Allen finally had to kill two of the animals.
Upon seeing a herd of Thomson's gazelles, Ava Gardner's character jokes that the species is named after a third basemen for the Giants who hit a home run to win the pennant. This is a reference to the baseball player Bobby Thomson of the New York Giants, whose famous 1951 home run against the Brooklyn Dodgers won the pennant for the Giants.