Brennan was as interim director of the National Counter-terrorism Center immediately after its creation, and since 2005 has served as CEO of The Analysis Corp., Wikipedia.com reported.

Since 2007, Brennan has served as chairman of the Intelligence and National Security Alliance.

As deputy national security adviser for homeland security in the president-elect administration, he will oversee plans to protect the country from terrorism and respond to natural disasters.

The president-elect's appointment comes six weeks after Brennan was forced to remove himself from consideration for the CIA directorship because of concerns that his statements supporting controversial interrogation techniques would complicate his confirmation, The Washington Post reported.

The firm Brennan heads and its corporate parent have earned millions of dollars during the past 10 years helping several federal agencies and private firms on counter-terrorism.

The Analysis Corp.'s parent, Global Strategies in London, has been criticized in the media about alleged harsh actions by its soldiers-for-hire in Afghanistan and Iraq, the Post said. Brennan also has attracted criticism from human rights experts for defending the CIA's practice of forced transfers of terrorism suspects for interrogations, which lead to his withdrawal from consideration to head the agency.

Aides said Obama accepted Brennan's assurances that he did not help in establishing abusive interrogation practices at the CIA.

One of Brennan's first tasks, Obama aides said, will be to examine whether most of the Homeland Security Council staff should be folded into the National Security Council. A transition spokeswoman told the Post said that while no decision has been made, the idea was was recommended by several Obama advisers and independent experts.