As a poor immigrant who served Israel faithfully and was privy to the inner sanctum of its defence establishment, he might have been a model Zionist.
Instead, Mordechai Vanunu blew away the Jewish state's nuclear secrecy in a newspaper interview.
Vanunu, 49, was released yesterday after an 18 year prison term for treason.
The former atomic technician is widely despised as a traitor in Israel and has been disavowed by most of his family.
But he has become an international cause celebre during his time in prison, embraced as a hero by the anti-nuclear movement and nominated repeatedly for the Nobel Peace Prize.
Vanunu, a Moroccan-born Christian convert, now wants a new life abroad, but has been indefinitely barred from leaving Israel.
He says he has no more secrets to spill, but vows to keep campaigning against Israel's nuclear arsenal and maybe the state itself.
"There is no need for a Jewish state. There should be a Palestinian state," Vanunu said in a jail interview leaked ahead of his release by security services.
The remarks were sure to stir more ire among Israelis.
The second of 10 children raised in a religious home, Vanunu emigrated from his native Marrakesh in 1963.
He studied hard and served in a military combat unit, seeing action in the 1973 Middle East war. Vanunu started work at the Dimona reactor in 1976 after passing rigorous security tests. He was noted for his dedication.
Then Vanunu enrolled in Ben-Gurion University's philosophy program, and doubts set in. Classmates recall an intense, complex, contradictory character - at times ascetic, at others driving a flashy sports car, shy with women but on one occasion doing a striptease.
All agree that contacts with Arab students changed his views. Abandoning Jewish practice, he formed a far-left group and refused reserve duty in Israel's 1982 invasion of Lebanon.
Vanunu's work continued despite displays of disaffection, until he was fired in 1985 and set off on a world trip. In his backpack, he carried two rolls of film shot inside Dimona.
Vanunu converted to Christianity in Sydney where he brought up his Dimona experiences in a chat with a Colombian freelance journalist who looked for a paper to run the story.
The offer reached Peter Hounam of Britain's Sunday Times, who flew Vanunu to London to be questioned by scientists.
"We debriefed him for five weeks. When he did not know the answer to a question, he said so," Hounam told Reuters, adding that the paper promised Vanunu $US100,000 ($A137,000 at present exchange rates) for any book deal.
He would never collect.
Mossad at first considered killing Vanunu, according to a former chief of the Israeli spy agency, but opted for abduction instead. Using a blonde agent known as Cindy for a honey-trap, Mossad lured Vanunu to Rome, where he was bundled up and shipped to Israel to be tried for treason.
Tried in secret, he revealed to the world he had been kidnapped by pressing a message on his palm against a police van window.
Vanunu's revelations on Dimona led independent experts to conclude Israel had stockpiled from 100 to 200 nuclear warheads.
Israel has never acknowledged developing atomic weapons and has never signed the nuclear non-proliferation treaty. Its policy of deliberate ambiguity is designed to deter Arab enemies while avoiding international condemnation.
On his release, Vanunu was greeted by throngs of cheering supporters who hailed him as a "peace hero" while counter-demonstrators branded him a traitor.
In letters, he has said he wants to emigrate, start a family, and lecture on American history.
But many believe he will first have to deal with psychological scars from his incarceration, two thirds of which was spent in solitary confinement.
"Mordechai is not crazy, but he is very angry and sometimes suffers from notions that there is a vast Israeli conspiracy against him," said Vanunu's brother, Meir.
Reuters