President Obama talks with Ricardo Zuniga, Senior Director for Western Hemisphere Affairs, in the Oval Office, Dec. 17, 2014. (Official White House Photo by Pete Souza)

This post has been updated.

When Ricardo Zuniga walked into a meeting of senior directors of the National Security Council Thursday, the entire room stood up and gave him a rousing round of applause.

Zuniga and Deputy National Security Adviser Ben Rhodes had just brokered a huge change in U.S. relationship with Cuba, normalizing relations with the country for the first time since the Cold War. The men, who a senior administration official described as "two halves of the same person," conducted nine rounds of secret talks with the Cubans over a year and a half in Canada and at the Vatican.

Rhodes's trajectory,  from former aspiring fiction writer to speechwriter to one of Obama's most trusted advisers,  has been well chronicled. Zuniga, on the other hand, has spent most of his professional life working in relative obscurity, toiling outside the spotlight in Washington and abroad, including stints in Havana. The official said Rhodes was chosen to underscore that there was a direct channel to the Oval Office. Zuniga was picked because he has extensive ties to, and experience in, Cuba.

"This is his bread and butter," the official said of Zuniga. "He was always going to be involved with this."

Boyish looking at 44, with a mop of dark hair, Zuniga was named senior director for Western Hemisphere affairs at the National Security Council in 2012. He is a career foreign service officer who has worked for the State Department, where he was acting director of the Office of Cuban Affairs in the Bureau of Western Hemisphere Affairs. He served as a human rights officer at the U.S. Interests Section in Havana, the office that the U.S. keeps in Cuba and routes all contact with Cuba through the Swiss government. He has also worked as a Cuba and Caribbean analyst, and has been posted in Brazil, Spain, Mexico and Portugal.

The administration had made changes to its Cuba policy, loosening travel restrictions and making it easier to send remittances to the island, and was looking to do more when the security council job came open.

"I don't think it's an accident that someone with Ricardo's background ended up in the job," said Dan Restrepo, who preceded Zuniga at the NSC. Zuniga was a "true subject matter expert" on regulations against the island and its broader policies and politics, and has been able to do what few have: slip into the tightly-knit group of long-time advisers that surround President Obama.

"That combination was not by accident," Restrepo said.

Zuniga has broad experience throughout Latin America, having worked in Brazil and Mexico. Born in Honduras, he is the grandson of Ricardo Zuñiga Augustinus, a longtime National Party politician who was an ally of the country's military regimes. Zuñiga Augustinus ran unsuccessfully for president in the early 1980s. His political party turned anti-communist after  President Ronald Reagan was elected.

Zuniga is a graduate of the University of Virginia. He is married and has two daughters. Former and current colleagues describe him as affable, low-key and humble in an arena with outsize personalities. One current co-worker said he is "scared to death" Zuniga will leave because he is so much fun to work for.

A person who works with Zuniga was going through a rough patch personally. Even though he was working around the clock, Zuniga took the time to check in with about this person's personal life. Zuniga throws parties for his staff at his house and pops by happy hours.

"He's very affable," said Luis Miranda, the former White House director of Hispanic media. "He laughs at a good joke and he's very lively when he gets worked up. And when he talks you can see he knows exactly what he's talking about."

Zuniga's time in Cuba made him especially attuned to issues of civil society and free speech in Cuba, issues he pushed with the Cuban government.

"He had serious issues with the human rights situation and he still does," an official said.

He kept in close touch with advocacy groups like Cuba Now that were pushing for the U.S. to change its policies toward the island. In 2003, Zuniga was given an award for his "comprehensive reporting and on-the-money strategic analysis. His work with human rights groups and activists in Cuba was substantial," a write-up read.

"It was incredibly helpful to have somebody who really wanted to sit down and figure this out, ask the tough questions but always in the spirit of we want to figure this out and we want to do right by you guys, we want to do right by the Cuban American community, want to do right by the Cuban people," said Ricardo Herrero, Cuba Now's director.

An official said Zuniga knew that dissidents and others on the island wanted greater access to the Internet and telecommunications, something he pushed in the talks. Zuniga was also able to read the Cuban government in a way that Rhodes and others were not.

He was able "in a way that maybe others could not to bring creative ideas to the table and say, 'I think they're really holding firm to this' or 'this is a game of chicken.'"

Zuniga seemed attuned to the most minute of details, from making sure the paper had correct hole punches in the briefings to the president. He was the person responsible for timing the transfers on Wednesday, deciding when a plane carrying American contractor Alan Gross, who was in a Cuban prison for five years and released on humanitarian grounds, was ready to leave Cuba and when the flight carrying three men released from U.S. prison as part of the deal would land in Cuba.

"He was the one monitoring, saying, 'okay, we have wheels up,'" a senior administration official said.

Another official said Zuniga feels great about having pulled off the deal, which was uncertain until very recently. But the president had made clear that the Cuba deal was something he wanted.

"This guy was working essentially 24/7 to get this done since they started negotiations," this official said of Zuniga. "It's insane."