Steve McQueen accepted the role of Hilts on the condition that he got to show off his motorcycle skills.
Steve McQueen also personally attempted the jump across the border fence, but crashed. The jump was successfully performed by Bud Ekins.
Steve McQueen held up production because he demanded that the script be rewritten to give his character more to do.
Steve McQueen's character Hilts was based on amalgamation of several characters, including Major Dave Jones, a flight commander during Doolittle's Raid who made it to Europe and was shot down and captured and Colonel Jerry Sage, who was an OSS agent in the North African desert when he was captured. Col. Sage was able to don a flight jacket and pass as a flier otherwise he would have been executed as a spy. Another inspiration was probably Sqn Ldr Eric Foster who escaped no less than seven times from German prisoner-of-war camps.
John Leyton who played Willy, the Tunneler, was one of the most popular UK pop singers in the early '60s. He recorded the title song with lyrics.
Donald Pleasence had actually been a Royal Air Force pilot in World War II, who was shot down, became a prisoner of war and was tortured by the Germans. When he kindly offered advice to the film's director John Sturges, he was politely asked to keep his "opinions" to himself. Later, when another star from the film informed John Sturges that Pleasence had actually been a RAF Officer in a World War II German POW Stalag camp, Sturges requested his technical advice and input on historical accuracy from that point forward.
Donald Pleasence's character was based partly on London-born John Cordwell, later a Chicago architect and then proprietor of the Red Lion Pub on the city's N. Lincoln Avenue. Cordwell died in 1999. Stories about him and the Red Lion are told from various points of view in the collection "Tales from the Red Lion" (Chicago: Twilight Tales, 2007, ISBN 0977985623).
Richard Attenborough was an RAF air gunner/photographer who served in the RAF for three years unlike his character, based on Squadron Leader Roger Bushell who was a Spitfire Pilot in 92 Squadron in the early years of World War Two.
Richard Attenborough was cast at short notice after the first choice pulled out.
Charles Bronson, who portrays the chief tunneler, brought his own expertise and experiences to the set: he had been a coal miner before turning to acting and gave director John Sturges advice on how to move the earth. As a result of his work in the coal mines, Bronson suffered from claustrophobia just as his character had.
James Garner developed his "Scrounger" character from his own personal experiences in the military during the Korean War.
Paul Brickhill, who wrote the book from which the film is based, was piloting a Spitfire aircraft that was shot down over Tunisia in March 1943. He was taken to Stalag Luft III in Germany, where he assisted in the escape preparations.
Wally Floody, the real-life "Tunnel King" (he was transferred to another camp just before the escape), served as a consultant to the filmmakers, almost full-time, for more than a year.
According to David McCallum, the barbed wire that Hilts (Steve McQueen) crashes into near the end of the film, which was actually made of rubber, was made by the cast and crew during their free time by tying small pieces of rubber around larger ones.
Although Steve McQueen did his own motorcycle riding, there was one stunt he did not perform: the hair-raising 60-foot jump over a fence. This was done by McQueen's friend Bud Ekins, who was managing a Los Angeles-area motorcycle shop when recruited for the stunt. It was the beginning of a new career for Ekins, as he later doubled for McQueen in Bullitt and did much of the motorcycle riding on the television series CHiPs.
During idle periods while 'The Great Escape' was in production, all cast and crew members - from stars 'Steve McQueen' and James Garner to production assistants and obscure food service workers - were asked to take thin, five-inch strings of black rubber and knot them around other thin strings of black rubber of enormous length. The finished results of all this knotting were the coils and fences of barbed wire seen throughout the film.
During production, Charles Bronson met and fell in love with David McCallum's wife, Jill Ireland, and he jokingly told McCallum he was going to steal her away from him. In 1967, Ireland and McCallum divorced, and she married Bronson.
During the climatic motorcycle chase, John Sturges allowed Steve McQueen to ride (in disguise) as one of the pursuing German soldiers, so that in the final sequence, through the magic of editing, he's actually chasing himself.
For the train sequences, a railroad engine was rented and two condemned cars were purchased and modified to house the camera equipment. Scenes were shot on the single rail line between Munich and Hamburg, and a railroad representative was on hand to advise the filmmakers when to pull aside to avoid hitting scheduled oncoming trains.
Hilts (Steve McQueen) strings a wire across the road to obtain a motorcycle. McQueen himself played the German motorcyclist who hits the wire.