The film begins with the then-recent US Army Ranger raid at Cabanatuan prisoner-of-war camp. The film then flashes back to March 1942.
As the U.S. Army under General MacArthur struggles to hold on at Bataan against the Japanese, Colonel Joseph Madden (John Wayne) orders one of his officers, Captain Andrés Bonifácio (Anthony Quinn), to shape up. Bonifácio has been under a strain because his sweetheart Dalisay Delgado (Fely Franquelli) is apparently collaborating with the Japanese, broadcasting propaganda over the radio.
Later, Madden is picked to slip through the lines to organize Filipinos to fight as guerrillas against the occupying Japanese forces. His commanding officer lets him know that Delgado is actually using the propaganda broadcasts to secretly transmit valuable information to them, but he is ordered to reveal that fact to no one, not even Bonifácio.
Madden makes contact with one group of Filipino resistance fighters, but as they set out to on their first mission, they encounter middle-aged American school teacher Bertha Barnes (Beulah Bondi). She and her students join the guerrillas after the Japanese hang Buenaventura Bello (Vladimir Sokoloff), the principal of her school and a dear friend, for refusing to take down the American flag.
Setting out on their first mission to destroy a Japanese gasoline dump, Madden and his men stumble upon the Bataan Death March and realize that Bataan has fallen. Many of the Filipinos lose heart, so to fan their will to fight, Madden finds and engineers the rescue of Captain Bonifácio from the Death March. Bonifácio happens to be the grandson of Andrés Bonifacio, a national hero. It works; for the group's first mission the guerrillas come to the Flilipino village and hang the Japanese officer who ordered the killing of Bello; and over the next year, Madden and his guerrillas attack Japanese outposts, supply depots, military airfields and other installations.
Major Hasko (Richard Loo), one of the Japanese commanders, attempts to appease the local population by staging a semi-independence ceremony to reduce popular support for the Filipino resistance. Madden, Bonifácio and the guerrillas attack the ceremony, where Dalisay finally reveals her true alliance when, during her radio broadcast, she urges her people to rise up against the Japanese. Most of the Japanese troops are killed in the raid, but young Filipino boy Maximo Cuenca (one of Barnes' students) is captured. After being beaten, he agrees to lead the Japanese to the Madden's hideout. However, as they near the spot, Maximo grabs the steering wheel of the Japanese truck, sending it careening down a mountainside. He dies in the arms of Miss Barnes.
Later, Colonel Madden is ordered out of the field, leaving Captain Bonifácio in command of the Filipino resistance. Several months later in October 1944, Bonifácio and his group travel to Leyte, where rumors are circulating of the impending American invasion to liberate the Philippines. After arriving on Leyte, Bonifácio is reunited with Madden. They are given the mission of taking and holding a small village to block Japanese reinforcements from repelling the impending American landing.
By trickery, Madden, Bonifácio and their men engage and defeat the Japanese garrison in a fierce pitched battle. However, two enemy soldiers get away on a motorcycle to spread the alarm. Japanese tanks and soldiers attack. The defenders manage to knock out most of the tanks, but are on the verge of being forced to retreat. Just when all seems lost, American reinforcements and tanks arrive and turn the tide of the battle.
The film closes with another short montage of several of the actual released Americans from the Cabanatuan prison camp.John Wayne as Col. Joseph Madden
Anthony Quinn as Capt. Andrés Bonifácio
Beulah Bondi as Bertha Barnes
Fely Franquelli as Dalisay Delgado
Richard Loo as Maj. Hasko
Philip Ahn as Col. Koroki
Alex Havier as Sgt. Bernessa
'Ducky' Louie as Maximo Cuenca
Lawrence Tierney as Lt. Cmdr. Waite
Leonard Strong as Gen. Homma
Paul Fix as Bindle Jackson
Abner Biberman as Japanese captain at schoolhouse
Vladimir Sokoloff as Señor Buenaventura J. Bello
As the film opens, the credits roll over actual film clips from January 30, 1945, of POWs being freed from Cabanatuan, a Japanese prisoner of war camp.
Producer and future production partner of John Wayne Robert Fellows had previously made two war films with fictional characters based on true incidents in the War in the Pacific; Bombardier based on the Doolittle Raid and Marine Raiders and also produced the John Wayne western Tall in the Saddle for RKO. Fellows strongly believed that an account of the initial defeat and guerilla resistance of the American and Filipino forces as well as MacArthur's return would be a splendid tribute and a profitable film. Fellows contacted the Office of War Information and the American military who agreed as well as provided their assistance.
The film took 130 days to shoot based on the rapidly changing news of the time. Two thirds of the way through filming, the invasion of the Philippines occurred, forcing several script changes and rewrites in order to keep up with current events. The Raid at Cabanatuan and release of prisoners was also rapidly incorporated into the screenplay with scenes of a recreation of the 6th Ranger Battalion attacking the prison camp placed on the beginning of the film with appearances of recently released prisoners added to the end of the film.
Ben Barzman's screenplay emphasized Filipino nationalism as much as American patriotism. A Filipino school principal who reminds a Filipino schoolboy of Philippine nationalism is later ordered by the Japanese conquerors to take down the American flag in his schoolyard. When he refuses to do so, the Japanese hang him from the same flagpole.
The soundtrack reused large sections of Max Steiner's score for King Kong; a small section where they play the music to the British national anthem.
Back to Bataan was Wayne's first encounter with Americans with open Communist sympathies and beliefs, as during the filming, Barzman and director Edward Dmyrtyk were outspoken about their communist views. When Wayne heard that Barzman and Dmytryk were openly belittling the religion of the film's technical advisor, Colonel George S. Clarke (who had commanded the 57th Infantry Regiment of the Philippine Scouts during the Battle of Bataan and was roughly Wayne's real life counterpart), and mocking him with renditions of the Internationale, he confronted Dmytryk, asking him if he was a Communist. Dmytryk replied that he was not, but if "the masses of the American people wanted communism it would be good for our country. Though Dmyrtyk denied he was a communist, Wayne felt that he was by his use of the word "masses". By contrast, Barzman's wife Norma recalled Wayne being friendly with her husband, with Wayne hugging him and calling him a "goddammned communist", to which Barzman jokingly replying that Wayne was a "fascist".
During the filming, Dmytryk and Barzman found out that Wayne refused to use a stunt double, so they collaborated in writing scenes that they thought would make Wayne insist on a stunt double to do the painful scenes. In one scene, Wayne was required to be lifted in the air by leather harness to simulate being blown by an explosion, and in another, Wayne and Quinn had to enter an icy pond and remain underwater for a lengthy time, each breathing through a reed. Wayne did the stunts, but as he drank a bracing whiskey, he told Barzman, "You better be goddamn sure we don't find out this is something you dreamed up out of your little head as a parting gift".
In her book The Star-Entangled Banner, Sharon Delmendo views the film as Wayne being a surrogate for Douglas MacArthur. He has to face the wrath of his Filipino officers asking him where American help is, then later leaves the Philippines by submarine to return like MacArthur, in the invasion.