WASHINGTON — There were 79 people on the assault team that killed Osama bin Laden, but in the end, the success of the mission turned on some two dozen men who landed inside the Qaeda leader’s compound, made their way to his bedroom and shot him at close range — all while knowing that the president of the United States was keeping watch from Washington.

The men, hailed as heroes across the country, will march in no parades. They serve in what is unofficially called Seal Team 6, a unit so secretive that the White House and the Defense Department do not directly acknowledge its existence. Its members have hunted down war criminals in Bosnia, fought in some of the bloodiest battles in Afghanistan and shot three Somali pirates dead on a bobbing lifeboat during the rescue of an American hostage in 2009.

The raid early Monday in Pakistan has nonetheless put a spotlight on a unit that has been involved in some of the American military’s most dangerous missions of recent decades.

Leon E. Panetta, the director of the Central Intelligence Agency, said the Seal commandos went into the mission with only a 60 percent to 80 percent certainty that Bin Laden was in the compound. Mr. Panetta said the commandos made the “split-second decision” to shoot him — the unarmed Qaeda founder had a rifle within reach, an American official said Wednesday — when they found him in his third-floor bedroom.