Colonel Saito was inspired by Major Risaburo Saito, who, unlike the character portrayed in this movie, was said by some to be one of the most reasonable and humane of all of the Japanese prison camp commandants, usually willing to negotiate with the P.O.W.s in return for their labor. Such was the respect between Saito and Lieutenant Colonel Toosey (upon whom Colonel Nicholson was based), that Toosey spoke up on Saito's behalf at the war crimes tribunal after the war, saving him from the gallows. Ten years after Toosey's 1975 death, Saito made a pilgrimage to England to visit his grave.
Initially, Sir Alec Guinness had doubts about playing the role of Colonel Nicholson. Guinness had become a much-loved figure on-screen, appearing in a series of popular comedies. The Nicholson character seemed humorless, unlovable, and perhaps even dull. To remedy this, Guinness tried to inject some humor into his portrayal of the Colonel. Director Sir David Lean was very much opposed to this idea, insisting that it be played straight. Thus began an argument between the two men that continued throughout filming.
At one point during filming, director Sir David Lean nearly drowned when he was swept away by a river current. Actor Geoffrey Horne saved his life.
The elephants employed in helping build the bridge would take breaks every four hours and lie around in the water, whether the crew wanted them to or not.
Sessue Hayakawa (Colonel Saito) edited his copy of the script to contain only his lines of dialogue. This way, he remained oblivious to the real nature of his character's fate.