In the 50 years of their existence, the SEALs have gone from being a unit unknown outside the military to one squarely in the international spotlight. The irony is that men who are members of the SEAL community do not usually seek to call attention to themselves. But their high-risk/high-reward missions also contain high drama, and that has made them world famous.

SEAL heritage has its roots in World War II with four units: the Amphibious Scouts and Raiders, who conducted amphibious reconnaissance and commando operations in Europe and the South Pacific; the Naval Combat Demolition Units (NCDU), who were assault demolitions experts and cleared the beachheads for Operations Overlord and Dragoon; maritime operators of the Office of Strategic Services; and probably the most widely known group, the Underwater Demolition Teams (UDTs), who were combat swimmers who conducted hydrographic reconnaissance and pre-landing beachhead obstacle demolition in the Pacific.

In the postwar downsizing that affected all military branches, only the UDTs survived – barely. And even their value was questioned. UDT existence was saved by the outbreak of the Korean War in 1950. In addition to reaffirming the crucial contribution UDTs provide to amphibious operations, the Korean War also revealed the need to expand UDT capability. In the mid- to late 1950s, studies were begun to identify what those capabilities should be and what would be needed to accomplish these new goals. In order to expedite the process, the ranks of the new unit, named SEAL for SEa, Air, and Land, would initially be composed of UDT members. By the time two SEAL teams were authorized in January 1962, enough of the doctrine, training regimen, and material requirements were in place so that SEAL Team One, based in Coronado, Calif., and SEAL Team Two, based in Little Creek, Va., were able to become fully operational within days of authorization.

But nobody outside of a select few on the “need to know” list was aware of the SEALs. The SEALs would finally “go public” in 1967, when television documentaries and newspaper articles about them and their missions were approved.

At first, SEAL teams used a lot of equipment, weapons, and transport developed for UDTs. But because their scope of operations was broader than that of the UDTs, they began to design and purchase an inventory suited to their specific needs. This included specialized underwater breathing apparatuses, surface and subsurface transport vehicles, parachutes, and other systems. Though some SEALs had participated in parts of Operation Mongoose against Cuba, it was in Vietnam that SEALs came into their own.

SEAL operations in Vietnam came about as a result of findings made by Lt. David Del Giudice and Ensign Jon Stockton, who visited MAAG-V (Military Advisory Assistance Group-Vietnam, the predecessor to Military Assistance Command Vietnam-MACV) in order to establish liaison with the command and to identify requirements for SEAL involvement in country. Upon their return to the states, Del Giudice and Stockton made a series of presentations to their superiors, and in March 1962, SEAL Team One personnel began arriving in South Vietnam. At this stage of the conflict, the role of SEALs was that of training and advising their South Vietnam military counterparts, which they did from 1962 to 1964 as part of guerrilla operations targeting sites in North Vietnam, part of Operation Plan 34A.

Following the Tonkin Gulf incident that resulted in the escalation of American military operations in the region, SEALs were administratively transferred to the joint unconventional warfare task force called U.S. Military Assistance Command Vietnam, Studies and Observation Group (USMACV SOG). As its name suggests, it was responsible for all covert and special operations missions in the theater. SEAL operations dramatically increased and spread throughout the country. They came to include reconnaissance patrols, direct action missions, Operation Bright Light POW rescue missions, Phoenix Program missions against Viet Cong cadres, and more.

As the months passed, SEAL missions began shifting south to the Rung Sat Special Zone just 7 miles south of the South Vietnamese capital of Saigon (now Ho Chi Minh City), a longtime communist stronghold.

On Oct. 28, 1965, a mortar barrage killed Cmdr. Robert J. Fay, making him the first SEAL to die in Vietnam. On Aug. 19, 1966, Radarman 2nd Class Billy Machen was killed on a mission in the Rung Sat, the first to die in a combat mission. Eventually 46 SEALs would give their lives in Vietnam. Aggressive patrolling by SEALs in the Rung Sat resulted in a dramatic decrease in communist Viet Cong guerrilla activity. That success resulted in the request for more SEAL teams, particularly in the Mekong Delta, another region that was a longtime communist stronghold. The demand for SEALs eventually outstripped supply capabilities from SEAL Team One, and by 1967, members of SEAL Team Two were conducting missions in South Vietnam.

SEALs became so effective that the Viet Cong called them “The Men with Green Faces” out of respect, and posted cash bounties for the killing of a SEAL. Vice Adm. Elmo Zumwalt, commander, U.S. Naval Forces in Vietnam and the Naval Advisory Group, Vietnam, was so impressed that he wanted “hundreds” of SEALs in Vietnam. By the time the war ended, given the relatively small number of personnel stationed in the country, the SEALs were one of the most highly decorated units in the war, with members receiving three Medals of Honor, two Navy Crosses, 42 Silver Stars, 402 Bronze Stars, two Legions of Merit, 352 Navy Commendation Medals, and three Presidential Unit Citations.