Pushing a strongly liberal-left agenda, Sharpton has earned popularity for his fiery defence of ethnic minorities, especially blacks and Latinos, and notoriety for his outspoken attacks on powerful white interests.
Sharpton stands to do well in places like Washington DC (whose district he wants to make a state), and other heavily black areas. And his stand on jobs, healthcare, education and the environment has appeal for those on the liberal left.
But his reputation as a radical firebrand – and the obstacles any black candidate faces in a white-dominated political system – doom him as an also-ran.
Al Sharpton was born in New York in 1954. In a religious career that set off like catapulted cardinal, young Al was preaching from the age of four and became an ordained minister aged just nine.
Sharpton developed an interest in social issues as a teenager, and was the youth director of Reverend Jesse Jackson's Operation Breadbasket from 1969 to 1971. He founded the National Youth Movement (later the United African Movement) in the early 1970s, an organisation aiming to fight drugs and raise money for deprived youths.
Alfred Charles Sharpton
Spouse: Kathy Jordan
Current post: None
Military record: None. (Too young for Vietnam war)
But he varied his time by working as soul singer James Brown's touring manager from 1973 until the 1980s, and as a youth organiser for notorious boxing promoter Don King from the late 1970s to the early 1980s.
His championing of black defendants in high profile racial assault cases in the 1980s brought Sharpton national attention – and controversy, notably when he backed black teenager Tawana Brawley's hoax claim that she was raped by a white gang.
Sharpton has shown more persistence than success on the political stage. He ran for the New York state Senate in 1978, for the national Senate in 1992 and 1994, and tried to become New York mayor in 1997.
His popularity surged in September 1999, when he led multi-ethnic rallies after the police killing of West African immigrant Amadou Diallo, boosting his profile nationally.
Socially liberal (pro-abortion, pro-gay marriage, anti-death penalty), Sharpton is a firmly on the left of his party.
Off the wall: Sharpton (L) has
promoted blacks in all industries
He would repeal the Bush tax cuts and put the money towards universal healthcare, expanding education access and enhancing environmental protection. He wants to spend $250 million creating new jobs.
He called the anti-terrorist Patriot Act "an absolute assault on the civil liberties of all people in this country" and criticised racial profiling suffered by Arab and Muslim Americans.
Sharpton has been highly critical of the war and questioned White House claims of an Iraqi threat. “If you can find the weapons before the war, how come you can't reveal the weapons now?” he demanded.
An advocate of multilateral cooperation, Sharpton wants a more consistent foreign policy, saying the US often tolerates some brutal dictatorships while applying pressure on minor offenders. He would lift sanctions from Cuba.
He opposes many free trade agreements like NAFTA, saying they sacrifice workers' rights and the environment, and argues for "fair trade" agreements.
He says the US should take a more balanced approach to the question of Palestine and to "engage in a real relationship with allies in the Arab world". But he wants an investigation of Saudi Arabia's ties to the Bush administration.
"Someone who will be an active voice about issues of concern to African American business people."
- Robert Johnson, billionaire cable television mogul
"A professional troublemaker accused of not paying his taxes and found guilty of defaming innocent public officials."
- Robert Novak, syndicated columnist
Sharpton is seen by many as an unrepentant rabble-rouser whose past is too dodgy for him to be electable. He had to pay $65,000 in defamation costs for accusing a New York prosecutor of raping Tawana Brawley. He also failed to file a tax return in 1986 and has been jailed for past protests.