WikiLeaks, the anti-secrecy group, began releasing documents from Brennan's private AOL account last week, days after a teenage hacker was reported to have claimed he had gained access to the account.
"I was certainly concerned about what people might try to do with that information," he told a conference on national security in Washington, criticizing the media for "giving air to what is criminal activity."
WikiLeaks publishes CIA chief’s email contacts
The documents released so far have included a contact list, policy recommendations on Afghanistan and Pakistan, and his family's addresses and phone numbers.
Although an embarrassment, the document dump has not exposed national security secrets, and Brennan appears to have stopped using the account in 2008 when he rejoined the government after a period in private life.
"I was certainly outraged by it," Brennan said of the hack, adding that he also was troubled by the way some of the media handled it.
"Because of some things that were put out, the implication of the reporting was that I was doing something wrong or inappropriate or in violation of my security responsibility, which was not certainly the case," he said.
He criticized the media's "ever-present thirst for trying to make something sexier and also of blowing it up more than it is."
"Giving air to what is criminal activity and propagating information I think was inappropriate," he said.
Government officials, he said, "also have family and friends, bills to pay, things to do in our daily life."
Use snail mail to thwart spies, Assange tells journalists
At the same time, the US spy chief said he recognized that the kind of hacking that he fell prey to reflects one of the undesirable realities of the Internet age.
"I think it does epitomize in many respects what we have to deal with in this increasingly modern and interconnected world. It's a reality of the 21st century," Brennan said.
"That's why I am talking about the legal structures that we need, the investigative capabilities that we need," he added.
"Because I see the role of government is to try to promote the security, the safety, the well-being and the prosperity of its citizenry.
"If it does not have the ability to do that in this increasingly cyber-environment, I think that the government is not fulfilling its primary responsibility to the people," Brennan said.
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