Before he received his code name of GARBO, Juan Pujol Garcia was a chicken farmer and hotel manager in Fascist Spain. He started his espionage career with no training, no contacts, and surrounded by intelligence agents from all sides. By the end of World War II, he would be awarded the Iron Cross Second Class from Hitler himself and made a member of the Order of the British Empire by King George VI. He was a bold double agent who greatly contributed to the success of the D-Day invasions, but the Nazis never realized they'd been had.
As Spain was torn apart by its civil war from 1936 until 1939, Pujol developed a distaste for both Fascists and Communists after being mistreated by both sides, though he had done his compulsory military service to Spain in 1931. When World War II broke out, he and his wife approached the British government to offer their services as informants. When they were rejected, Pujol created a fake identity for himself as a virulently pro-Nazi Spanish official and his spy career was born.
He considered the fight against the Nazis as one "for the good of humanity."
Instead of going to Britain to recruit more agents as his orders from Berlin would have had him do, he moved to Lisbon, where he started feeding his Nazi handlers terrible intelligence from open sources — all true, but useless —from tourism guides to England, encyclopedias and reference books, magazine ads, and even news reels. The Nazis accepted him and trained him based on how impressive-looking his reports were.
He soon had a fake network of his own agents and would blame them for faulty information. But it was when the Germans started hunting a fake convoy, created by Pujols, that British intelligence became interested in him. It was the British who dubbed him GARBO. He and his handler expanded their fake network, eventually having the Nazis pay for 27 spies that didn't exist. His reports were so long and grandiose he soon had to start transmitting to Berlin via radio. This did nothing to shorten the British effort to flood German intelligence with information that they would stop trying to infiltrate the British government.
His primary goal was deception. When Operation Torch came about, Pujols sent his Nazi handlers a letter, backdated via airmail, a warning about the invasion of North Africa. It was designed to arrive just too late to be of use but convince the Wehrmacht of his credibility. They took the bait. His finest hour came as part of Operation Fortitude, the massive Allied deception operation aimed at fooling the Germans about the D-Day landings. The Germans told Pujols they were concerned about the buildup for an invasion of Europe. Between January and June 1944, Pujols transmitted 500 times (four times a day) with planned snippets of information that would lead Hitler to believe Pas de Calais was the main target for the Allied and that Normandy was a diversion.
His deception kept 19 Nazi infantry divisions and two armored divisions at Pas de Calais, allowing the Allies to establish a beachhead in Hitler's Fortress Europe. Even after the landings, his broadcasts to Berlin managed to keep those units from moving for a full two months. British intelligence's official history of D-Day maintains that had Rommel moved those units to Normandy, they would "have tipped the balance" and the Allies might have been pushed back into the English Channel. The way he managed the Germans even won him more credibility and he was rewarded by Hitler himself, via radio, with an Iron Cross.
After the war ended, Pujol feared reprisals from surviving Nazis. He faked his death from Malaria in Angola in 1949 and went underground, running a bookstore in Venezuela. He died in Caracas in 1988.