He calls himself a wheeler dealer - an old-style power broker who maneuvers through a murky, dangerous world of intelligence, tribal intrigue and, some critics allege, guns and drugs, AP reported.
Ahmed Wali Karzai is also a half brother of Afghanistan's embattled president, whose international partners believe removing him from the country's political mix is essential if the newly elected administration is to prove its commitment to good governance.
So far, President Hamid Karzai has refused to push aside his brother without convincing proof he's done anything wrong.
Regardless of whether allegations against him are true, the 48-year-old brother has become a symbol of cronyism and a lightning rod for criticism of all that is wrong with Karzai's administration.
Although the only official post he holds is member of the Kandahar provincial council, Ahmed Wali Karzai is one of the most powerful men in Afghanistan - and one of the most controversial. At least six of his longtime friends refused to share childhood memories of him with The Associated Press, fearing critical recollections might get them in trouble with him.
The New York Times, citing current and former American officials, reported last month that the CIA pays Karzai for a variety of services, including helping to recruit an Afghan paramilitary force that operates at the CIA's direction in and around Kandahar.
Sen. John McCain, the ranking Republican on the Senate Armed Services Committee, has said the younger Karzai should leave Afghanistan for the good of the country.
Inside his gilded home in southern Afghanistan where Taliban insurgents are staging a violent comeback, the president's brother bristled at the litany of allegations against him. He blamed his political and tribal enemies for tarnishing his reputation.
He characterized claims that he's on the CIA payroll as "ridiculous." At the same time, he freely acknowledges that he works with the Americans, the Canadians and the British, providing information to "anyone who asks for my help."
On the streets of Kandahar, Afghans who are too afraid to be quoted by name say that Karzai's bodyguards are often called on to settle disputes, sometimes violently. He's accused of protecting local businesses with whom he shares tribal links or friendship, of controlling the police and giving orders to the mayor of Kandahar.
Speaking at his home, Karzai again denied involvement in the drug trade. He offered to take a polygraph test and said he was taking some of his accusers to court.
The president and his brother are among seven sons born to Abdul Ahad Karzai, tribal leader of the half million strong Popalzai tribe. The father was gunned down in Quetta, Pakistan. Although the culprits were never arrested, Ahmed Wali Karzai blamed the Taliban for his father's killing.
The president has been told by his international critics of the unsavory characters who knock on his younger brother's door in Kandahar, said one of two president's confidantes, who spoke on condition of anonymity because they feared crossing Karzai.
But the president is unmoved, telling them that tribal custom, not collusion, prevents his younger brother from turning away a fellow tribesman or a tribesman of any clan who comes to see him. Says the president: "Criminals and thieves knocked on my father's door but that didn't make him a criminal. This is our tribal custom. The tribal leader has to meet everyone.'"
A few decades ago, Ahmed Wali Karzai was just another obscure Afghan who left his country after the 1979 Soviet invasion. He and much of his family ended up in the U.S., where they owned restaurants in San Francisco, Boston, Chicago and Baltimore.
He managed the Chicago restaurant which closed in 1992. His rise to prominence began when Hamid Karzai was appointed head of a transitional government after the Taliban fell in 2001.
The younger Karzai might be guilty only of wheeling and dealing Afghan-style, lining up his allies with favors, flexing his tribal muscles with late night visits by his henchmen - who double as his bodyguards - and turning over his Taliban enemies to U.S. forces.
Like a king, he holds court in his home, doling out favors, punishing critics and rewarding friends. He readily acknowledges that his power comes from his brother's name.
"Yes, I am powerful because I am the president's brother," he said. "This is a country ruled by kings. The king's brothers, cousins, sons are all powerful. This is Afghanistan. It will change but it will not change overnight."