JERUSALEM (CNN) -- BBC correspondent Alan Johnston was released early Wednesday after being held for 114 days, ending the longest-ever captivity of a journalist kidnapped in Gaza.
Johnson smiles Wednesday in Gaza City, shortly after his 114-day ordeal as a hostage ended with his release.
Speaking live from Jerusalem, Johnston thanked his supporters and promised "to stay out of trouble," saying he was moved by all the people who took the time to support him when he needed it most.
"Thanks very, very, much, really to every one of you," Johnston said.
The knowledge that people were supporting his parents and holding vigils helped him stay hopeful and survive the difficulty of solitary confinement, Johnston said, adding that he knew the BBC "wouldn't let go."
The freed reporter said he was grateful for the support he received from friends as well as strangers.
All smiles after his first bath in 16 weeks, Johnston said he was glad to get "rid of that just-kidnapped-look," adding that he was looking forward to getting back to normal.
"The whole Johnston family is about to go back to the obscurity in which it was extremely happy for about 45 years," a jubilant Johnston said.
At a Jerusalem news conference, Johnston described his kidnapping and time in captivity as a surreal nightmare, saying that the mood of his captors changed after Hamas took control of Gaza in June.
"I'm sure if Hamas hadn't come in and stuck the heat on in a big way, I wouldn't have been released," Johnston said.
Johnston also thanked television broadcasters and international media outlets for keeping his story alive, saying that the worst fear for a kidnap victim is that "they're going to be forgotten in their wretched cell."
"Thank you for keeping my story alive," he said. Watch Johnston thank his supporters for not giving up »
Johnston said hearing his story along with messages of support on a radio he'd been given was "an extraordinary psychological boost."
The ordeal, which began when he was abducted March 12 by a group calling itself the Army of Islam, was "a nightmare, and I didn't think it would ever end," Johnston said.
"I am so glad to be free," Johnston told CNN's Ben Wedeman. "It's great to be able to talk to people like you."
Appearing at a news conference with former Palestinian Authority Prime Minister Ismail Haniya, Johnston said his captivity was "like being buried alive, really ... you didn't know when it might end."
Two or three months into his ordeal, Johnston said he found himself wondering how much longer he'd be held captive.
"The stresses are absolutely huge," he said. "It's a battle to keep your mind in the right place."
Johnston said he felt "unimaginable relief" upon his release.
"I've dreamt, literally dreamt, many times of being free again and I would always wake up in that room."
Johnston said he was finding it hard to believe that he will not wake up in captivity again.
In Lochgoilhead, Scotland, Johnston's parents told reporters they were having "a wonderful morning."
"We're absolutely overjoyed," said Graham Johnston. "It's been 114 days of a living nightmare."
"I never lost hope," a smiling Margaret Johnston said.
The Johnstons said they spoke with their son briefly on the telephone and had seen him on TV. "He looks fit. He looks strong. He looks well," said Graham Johnston.
Speaking to CNN, Director General of the BBC Mark Thompson applauded Johnston's "depth of understanding" about the Middle East conflict and the people in the region, something that gives his reporting an edge.
What comes next for Johnston is up to him, Thompson said, adding that the journalist has a bright future at the BBC but that it is up to him to decide how long he wants to take to "re-pressurize" and where he wants to take his career.
International news of coverage of Gaza has been stifled since Johnston was kidnapped. Thompson said there is no substitute for being on the ground and interacting with people at a "human level."
"As and when it's safe to deploy our correspondents in Gaza, we'd like to do that again," Thompson said.
The BBC's plans to deploy correspondents to the region in the future would be considered in the same way all dangerous deployments are, Thompson said, with the safety of journalists being a priority.
Johnston described his sense of isolation during captivity as intense, with death threats from his captors making his survival uncertain.
"There were times when I was really, really worried I would not survive it," Johnston said.
While his captors were not violent, he told reporters after crossing into Israel, they were often "rude and unfriendly" and sometimes threatened his life. He said he was chained briefly and became sick twice.
"The first month, I was in a place where I could see the sun, but for the last three months I was in a room where the shutters were always drawn ... so ... I couldn't see the sun at all," he said. "That was depressing."
"The very last place, the last two days, I could see it again."
Johnston was allowed by his captors to have a radio and was able to listen to the BBC World Service, he told Wedeman. He said hearing all the messages of support from those around the world and from his fellow journalists helped keep his hope alive.
His captors kept him in four different hideouts, he said, describing them as a "small jihadi group" with interests separate from the greater Israeli-Palestinian conflict. The kidnappers were more interested in "getting a knife into Britain" than changing conditions in the Palestinian territories, Johnston said.
Since Tuesday, Hamas had deployed forces around the Gaza City neighborhood where Johnston was being held, tightening their hold on the area and choking traffic in and out, Wedeman said, apparently gearing up for an assault on the building where the reporter was being held.
In the meantime, members of the Popular Resistance Committees were able to broker an agreement between Hamas and the Army of Islam calling for a joint prisoner release that would include Johnston.
As part of the deal, Hamas guaranteed that once Johnston was released, members of the Army of Islam -- who oppose Hamas and are seen as an obstacle to Hamas' domination of Gaza -- would not be harmed, sources told Wedeman.
Last week, the Army of Islam blamed Hamas militants for kidnapping two of its members and released a statement to media organizations including CNN renewing its threat to kill Johnston. The group also declared the "kidnappings" a declaration of war.
The group purportedly posted a video and audio statement from Johnston, who was clad in what appeared to be an explosives vest.
"I do appeal to the Hamas movement and the British government not -- not -- to resort to the tactics of force in an effort to end this," Johnston said in the statement posted on Islamic militant Web sites. Johnston warned that his captors would turn their hideout into a "death zone" if any rescue attempt was made.
The Army of Islam had demanded that Britain free radical Muslim cleric Abu Qatada, a Jordanian-born Palestinian who faced deportation to his home country. Qatada, known as Osama bin Laden's spiritual ambassador in Europe, is being held in Britain for suspected terrorist organization links.
The group also demanded Jordan free Sajida al-Rishawi, an Iraqi woman jailed for her involvement in a November 2005 wedding party suicide bombing, one of three near-simultaneous hotel bombings in Amman that killed 60 people. They also called for the release of Abu Mohamad al-Maqdasi, whose identity is unclear.
Little is known about the group, which also claimed to have taken part in the 2006 kidnapping of Israeli army Cpl. Gilad Shalit, who has not been released.
Israel used Johnston's release to make a plea on behalf of Shalit.
"The State of Israel congratulates BBC journalist Alan Johnston on his release ... and shares in the joy of his family and that of the entire British people," a statement from the prime minister's office said Wednesday. "Israel demands that soldier Gilad Shalit, who was abducted to the Gaza Strip over one year ago, also be released by his kidnappers, who belong to Hamas."
Days after they seized control of Gaza last month, Hamas officials said Johnston's release was imminent, but that was later disputed by an Army of Islam spokesman.
Johnston, 45, joined the BBC in 1991. He has spent eight of the past 16 years as a correspondent, including periods in Uzbekistan and Afghanistan, the BBC said. He was the only Western journalist based on Gaza. E-mail to a friend
CNN's Ben Wedeman contributed to this report