The President of the United States takes pride in presenting the DISTINGUISHED SERVICE MEDAL posthumously to CAPTAIN Joseph J. Rochefort, United States Navy, for services set forth in the following citation: For exceptionally meritorious service…while serving…as Officer in Charge of the Combat Intelligence Unit (Station HYPO) from March 1942 through June 1942. By virtue of his superb professional knowledge, astute guidance, and personal dedication, Captain (then Commander) Rochefort provided technical expertise and inspiring leadership to discover, analyze, and provide to the Fleet Commander-in-Chief astoundingly timely and accurate intelligence on Japanese naval plans and intentions leading to the Battle of Midway in June 1942. The information provided by Captain Rochefort’s Radio Intelligence Unit served as the singular basis for the Fleet Commander-in-Chief to plan his defenses, deploy his limited forces, and devise strategy to ensure U.S. Navy success in engaging the Japanese forces at Midway. His unrelenting efforts in this endeavor and the intelligence information he developed resulted in a Naval engagement with the Japanese fleet that is acknowledged as the turning point of the Pacific War. 
The words above are taken directly from Captain Joseph J. Rochefort’s posthumously awarded Distinguished Service Medal — at the time, the second highest medal in order of precedence just below the Medal of Honor. The story of what made this man, who journalist Elliot Carlson labeled “the Codebreaker who outwitted Yamamoto at Midway,” follows.
Joseph John Rochefort was born at the dawn of the 20th century on May 12, 1900. Many records indicate that Joe Rochefort was born in 1898 — others reflect a birthdate in 1899. It was a very young Joseph Rochefort’s sheer determination to join the Navy and participate in specific programs which account for such apparent discrepancies. In 1918, being just three weeks shy of his 18th birthday, he told the recruiting station he was born in 1899. A year later, he adjusted that date yet again to 1898 to meet the minimum age requirements for selection to the U.S. Navy’s Steam Engineering School at Steven’s Institute of Technology. Joe Rochefort was determined to serve in the United States Navy — the technicality of his actual birthdate was not going to get in the way.
His youthful age would not be the only obstacle that Joe Rochefort would have to overcome in order to realize his dream of serving in the United States Navy. Following his enlistment, Joe Rochefort applied for naval aviation. He wanted nothing more than to serve his country as a naval aviator. Unfortunately, with the war in Europe coming to a close, the Navy had no need for additional aviators and the Bureau of Navigation (BUNAV) denied his request. Undeterred, Rochefort sought a commission as an Engineer. Though he was successful, just three weeks after his commissioning, Ensign Joe Rochefort was removed from the active duty list and ordered to return home as part of the Naval Reserve. This short hiatus, however, was just a temporary setback. Five months later, the Navy offered him an opportunity to return to active status for duty aboard the oil tanker, USS Cuyama (AO 3), anchored off San Diego. And so, Joe Rochefort’s naval career began.
Captain Rochefort’s service in the Navy would be quite different from most of his counterparts at the time. As a junior officer, Joe Rochefort would spend five of his first seven years in the Navy serving aboard the Cuyama in various roles. While there was nothing unique about a naval officer serving at sea, it was what followed that broke from the norm.
In 1925, following a recommendation from Cuyama’s Commanding Officer — a recommendation based on Joe Rochefort’s knack for solving cross-word puzzles — he was assigned to the Navy’s Code and Signal Section, OP-20-G, under Commander Laurance Safford. Captain Rochefort would serve as Safford’s number two for the next four years before being assigned as an attaché in Japan where he studied the host country’s language and culture extensively.
Though Captain Rochefort excelled at cryptology and cryptanalysis, he did not seek out such positions. He wanted to go to sea. Going to sea is what the Navy expected of its officers and it was the ticket to upward mobility through the ranks. Craig Symonds, in his book, The Battle of Midway, writes: “Both Safford and Rochefort proved adept at the tedious and exacting work of code breaking, but they could not remain continuously in the job. Because the Navy expected its officers to serve at sea if they expected to be promoted, the two men adopted the practice of filling in for one another: Rochefort took over OP-20-G when Safford went to sea, and Safford resumed command when it was Rochefort’s turn to deploy.” And so it went for the better part of a decade and a half.
In June 1941, then Commander Joe Rochefort was assigned as Officer in Charge, Combat Intelligence Unit, Pearl Harbor, Hawaii — better known as Station HYPO. Up to this point, Captain Rochefort had proved himself as a naval officer and cryptologist, but it was here that he would leave his mark. Six short months after reporting, his world, and that of those around him, would change forever.
Following the December 7, 1941 Japanese attack on Pearl Harbor, Captain Joe Rochefort and his team of the Navy’s best cryptanalysts and linguists had one goal and one goal only: track the Imperial Japanese Navy (IJN). To do so, OP-20-G in Washington would have to allow HYPO to pursue the intercept and cryptanalysis of the Japanese naval code, or JN-25(b). With the same unrelenting determination which had been critical to overcoming so many other obstacles in his career, Joe Rochefort pressed the leaders in Washington and on December 17, 1941, authorization was granted to go after the naval code. Fueled by patriotism and a deep sense of guilt for failure to predict the recent attack, Station HYPO set about around-the-clock efforts to break, interpret, and analyze the operations and intentions of the IJN.
Early efforts resulted in the deciphering of multiple messages and operations orders — all of which pointed to the deployment of an occupation force in the Central Pacific. Exactly where in the Central Pacific remained a point of contention among many of the American leaders and intelligence analysts.
Months prior, Joe Rochefort had deciphered many of the Japanese two-letter, geographic designators for areas throughout the Pacific, including “AF” which he was confident equated to Midway Atoll. Despite his confidence and his proven ability as a cryptanalyst, many, particularly in Washington, doubted this intelligence. Admiral Nimitz however, trusted Captain Rochefort’s analysis and approved a ruse designed to trick the Japanese into confirming the location of “AF.” The ruse was successful and Admiral Nimitz proceeded with his plans to not only defend Midway Atoll, but to surprise the Japanese Kido Butai, or striking force, as they approached from the northwest. This intelligence gain would be the single most important breakthrough leading to American success at the Battle of Midway.
Without the persistent effort put forth by Captain Rochefort and his team at Station HYPO, the Battle of Midway would not be referred to today as the turning point in the War in the Pacific — at least not so in favor of the U.S. Navy. However, it was not just the collection and analysis of key intelligence that can be credited for the strategic victory. Captain Joe Rochefort earned the trust of his operational commander, Admiral Nimitz. He approached his work with the confidence of a man who knew his trade and knew his adversary. He was unrelenting in his recommendations based on his experience and keen analysis of the situation. As a result, Admiral Nimitz was able to place his forces in the right place and at the right time.
Captain Joseph John Rochefort was never formally recognized for his contributions to the War in the Pacific prior to his death in 1976. Though many tried during his lifetime — namely, Jasper Holmes — it was not until Rear Admiral Donald “Mac” Showers took up the crusade in 1981, that any real progress was made. Demonstrating the same grit and determination which so characterized Joe Rochefort, Admiral Showers succeeded. On May 30, 1986, surviving friends, shipmates, and family of Captain Joseph Rochefort gathered in the Roosevelt Room in the West Wing of the White House where the Distinguished Service Medal was awarded by President Reagan. The citation concludes: “Captain Rochefort’s distinctive accomplishments, tenacious commitment to excellence, and steadfast devotion to duty reflected credit upon himself and were in keeping with the highest traditions of the United States Naval Service.”
*For further reading, I highly recommend the references below.
 Carlson, Elliot. Joe Rochefort’s War: The Odyssey of the Codebreaker Who Outwitted Yamamoto at Midway. Annapolis, MD: Naval Institute Press, 2011. Print.
 Symonds, Craig. The Battle of Midway. New York, NY: Oxford University Press, 2011. Print.
 Toll, Ian. Pacific Crucible: War at Sea in the Pacific, 1941-1942. New York, NY: W. W. Norton & Company, 2012. Print.