The brainy South Bronx activist who stirred an Olympic torch-bearing ruckus in San Francisco said Thursday her conscience fueled her surprise anti-China protest.

A day after she used her torch-toting turn for a headline-grabbing pro-Tibet shoutout, Majora Carter was being showered with cheers and jeers.

"I figured it would not be smiled upon, but I thought it was freedom of expression," said Carter, 41, a 2005 recipient of a prestigious MacArthur genius grant.

"As a civil rights activist in this country, I could not have these privileges and not use them," Carter told the Daily News.

One of three New Yorkers chosen to bear the Beijing Olympic torch in San Francisco on Wednesday, Carter foiled an elaborate attempt by police to avoid thousands of demonstrators by pulling a Trojan horse-type ploy.

Once she got her hands on the Olympic flame, she pulled a Tibetan flag from her sleeve to protest China's human rights abuses in the Himalayan province.

A Chinese paramilitary squad escorting the torch quickly snatched it from her, and cops pushed her into the crowd.

Fellow torch-bearer Richard Doran, 57, a retired FDNY firefighter, called Carter's maverick move "disgusting and appalling."