It used to be known as “No Such Agency” — a play on its initials NSA. It was so secretive, its campus didn’t even have an exit sign on the parkway.

But the National Security Agency is finally emerging from the shadows. The famously circumspect spy service just launched a podcast. And now it’s willing to reveal details of work it once considered so sensitive, officials shared updates only on paper.

In exclusive interviews with The Washington Post, former NSA officers have opened up in detail for the first time about their role in the hunt for Osama bin Laden.

The broad contours of the pursuit are known from movies, books and countless articles, but while most Americans know about the role played by the CIA and the military’s Special Operations, few have a full picture of the NSA’s key contributions.

“It’s time for NSA to take some credit,” said Jon Darby, a retired NSA official who shortly after 9/11 was put in charge of figuring out new ways to go after al-Qaida’s communications.

The NSA was the agency responsible for intercepting and analyzing the calls that identified the key bin Laden associate who would eventually lead the CIA to the al-Qaida chief’s compound. It crucially placed the associate, a courier, in northwest Pakistan. And it determined, after the compound was identified, that he was still actively working for al-Qaida — with a degree of confidence that bolstered the intelligence community’s resolve to throw more resources at learning who lived in the compound.

With the launch this month of “No Such Podcast,” the NSA is seeking to publicize the role that signals intelligence, or SIGINT — the collection and analysis of electronic communications — plays in keeping America and its allies safe.

The massive scale of NSA collection on foreign targets —- some of whom communicate with Americans — has generated tension, with revelations a decade ago by former contractor Edward Snowden prompting debate about whether the surveillance was subject to sufficient privacy guardrails. Officials say such controversies have often obscured the work the agency does to bolster the nation’s security.

The first podcast episode goes back in time, before the Snowden revelations, to highlight the NSA’s role in the hunt for bin Laden, which ended with his killing in May 2011.

Darby told The Post the “nerve center” for the bin Laden hunt “was at CIA, but SIGINT was absolutely essential to finding him.”

Michael Morell, who was deputy director of the CIA at the time, said “finding Osama bin Laden was a team effort.”

Identifying the courier was a particular breakthrough, driven by two years of NSA wiretapping. Beginning in late 2007, the CIA shared with the NSA it suspected that a bin Laden associate known by his nom de guerre, Abu Ahmad al-Kuwaiti, might be related to the Ahmad Saeed family in Kuwait.

A top NSA analyst, whom Darby called his bin Laden “hunter in chief,” set his team to work. They pored through transcripts of calls. They tracked foreign numbers associated with those calls, daisy-chained them to other numbers and listened in on hundreds of conversations. Over two years, they built out the circle of individuals they thought might be Ahmad Saeed family members, recalled the now-retired analyst, who spoke on the condition of anonymity to protect him and his family from potential threats.

One person stood out: Ibrahim Ahmad Saeed, a Kuwaiti-born Pakistani, who spoke in Arabic and Pashto and kept very much to himself.

Almost alone among the spy agencies, the NSA had a roster of top linguists with the talent to understand not only both Arabic and Pashto but also Urdu and the targets’ peculiar verbal tics. “We were looking at how they pronounce different vowels and at little clicks in their speech,” he said.

Ahmad Saeed turned on his phone only sporadically, and mainly in busy urban areas or on highways in northwestern Pakistan, the analyst said. He never seemed to want to speak about himself, or invite any relative to visit — not even during major religious holidays. “It just raised our suspicions,” the analyst recalled.

The NSA ran comparisons of audio clips comparing the individual it knew as Abu Ahmad al-Kuwaiti with the intercepts of Ahmad Saeed. The lead analyst’s team reanalyzed material predating 9/11 and determined that the individuals known as Ibrahim Ahmad Saeed and al-Kuwaiti were in Afghanistan at the same time.

By late 2009, the hunter in chief was convinced. Ahmad Saeed and al-Kuwaiti were the same individual. “We had our guy,” he recalled thinking. And by then, they had also placed him in northwest Pakistan, but they didn’t know exactly where.

In the summer of 2010, with the NSA tracking al-Kuwaiti’s cellphone, the CIA deployed operatives on the ground to spot him, in part by correlating the phone’s signal strength to his location as he moved. Acting on a lead provided by the NSA, the CIA linked al-Kuwaiti to a white Suzuki Potohar, an SUV with an image of a white rhino on the spare-tire cover.

In August, using NSA cell signal data, the National Geospatial-Intelligence Agency, which analyzes drone and satellite imagery, identified a compound that stood out for its massive size and 18-foot walls. A CIA operative, working off NSA signals, trailed al-Kuwaiti as he drove from Peshawar, Pakistan, to the compound.

The crucial question now was whether the courier was still actively working for bin Laden. In November that year, a bin Laden team member approached the lead analyst. “I don’t know if this is of interest to you,” the team member said. He described a call between al-Kuwaiti and a friend in Kuwait.

“We’ve missed you,” the friend said. “Where have you been?”

“I’m back with the people I was with before,” came al-Kuwaiti’s cryptic reply.

The NSA had made another breakthrough: The intercept provided the confidence that al-Kuwaiti was an active al-Qaida member, not a retired terrorist.

“I remember going to my colleagues and saying, ‘This is kind of a big deal,’” the analyst recalled.

On the day of the raid, the NSA’s hunter in chief was in a Joint Special Operations Command center in Jalalabad, Afghanistan, hunched over his laptop, eyes glued to a special chatroom, tracking all communications with the agency in real time.

Back at Fort Meade, Darby was in a makeshift command center at the Ops1 Building with a handful of senior officials.

Darby, who by then was the agency’s counterterrorism chief, was at work all Sunday night. After the raid, he walked to an office where analysts had been working around-the-clock for a couple of weeks and told them: “We got Osama bin Laden.”

He didn’t get home until Monday night.

His wife, who had been in the dark all these years, finally realized what her husband had been involved in. She asked if he wanted a steak dinner.

“All I wanted,” he said, “was a pizza.”

Then he sat down. “I literally cried my eyes out, you know, shoulder shaking, let it all out, just crying my guts out,” he said. “It was just such an emotional release.”

Joby Warrick contributed to this report.