ARLINGTON, Va. — Alan Gross has called himself a “trusting fool” for going to Cuba in the first place. Family and friends described him with other words: gregarious and outgoing, with a talent for picking up and playing any musical instrument.

Gross, 65, was freed from prison Wednesday as part of an agreement that included the release of three Cubans jailed in the United States, officials said.

His wife, Judy Gross, has called him a humanitarian and an idealist, someone who was “probably naïve” and did not realize the risks of going to Cuba as a subcontractor for the federal government’s U.S. Agency for International Development.

Gross was arrested in 2009 while working in the Communist-run country to set up Internet access for the island’s small Jewish community, access that bypassed local restrictions and monitoring. Cuba considers USAID’s programs illegal attempts by the U.S. to undermine its government. Gross was tried and sentenced to 15 years in prison.

In court in Cuba, Gross called himself a “trusting fool” who never meant any harm to the Cuban government. But reports he wrote about his work showed he knew it was dangerous.

“This is very risky business in no uncertain terms,” he wrote in one report. A 2012 investigation by The Associated Press found he was using sensitive technology typically available only to governments.

During the five years he was imprisoned, family members said, Gross never grew angry at the Cuban people. He watched Cuban baseball and even jammed with his jailors on a stringed instrument they gave him. He kept in touch with family through weekly phone calls and passed the time reading books and magazines sent by his wife. The Economist, The Atlantic and Washingtonian were favorites.

On Friday nights, Gross, who is Jewish, would take out a picture of a group of friends celebrating the Jewish sabbath, and he would say the prayers they would say together.

But prison was tough on Gross. While in Cuban custody, he lost more than 100 pounds, developed problems with his hips and lost most of the vision in his right eye. In April 2014, after an AP story revealed that USAID secretly created a “Cuban Twitter” communications network to stir unrest on the island shortly after Gross was arrested, he went on a hunger strike for more than a week.

His mother, who was in her 90s, convinced him to start eating again. But she died in June 2014. Despite pleas from his family, Gross was not allowed to return to the United States for her funeral. After her death, he became withdrawn.

His wife and youngest of two daughters visited him in prison earlier in the year and he said goodbye.

“Life in prison is not a life worth living,” he told his lawyer, Scott Gilbert.

He vowed that his 65th birthday, which took place in May, would be the last one he celebrated in Havana, “one way or the other.”

Earlier, he had dreamed of getting out and planned what he would do.

His older sister, Bonnie Rubinstein, said in 2012 that he wanted to watch a Cuban baseball game as a free man. He also wanted to eat ribs and drink scotch when he got out of prison.

His brother-in-law, Rubinstein’s husband, even purchased a 12-year-old single-malt scotch he planned to save until his brother-in-law got home.

On Wednesday, a spokeswoman for the family said Gross and his wife walked hand-in-hand onto a military plane for the trip home. Onboard were bowls of popcorn, another thing he had missed, and a corned beef sandwich on rye. When the pilot announced they were leaving Cuban airspace, Gross stood up and took a deep breath.

His first telephone calls were two his two daughters.

“I’m free,” he told them.