Born into poverty in St Louis, Missouri, Gregory went to university on a track scholarship before he was drafted into the US Army,  where he got his start in comedy, through talent shows for the troops.

After his military service, he moved to Chicago in the hope of becoming a pro comic, and joined with fellow black comics including Bill Cosby, to try to work as themselves, breaking from the stereotypical 'minstrel'.

He started working in mainly black clubs, but occasionally would play to white audiences too - and it was one such performance where he was spotted by Hugh Hefner, who hired him to  work at the Chicago Playboy Club.

He became known as one of the first comedians to highlight the social inequality and prejudice encountered by black Americans on stage and on TV, where his career began with an appearance  on Jack Parr's Tonight Show

Gregory  is known for his activism as much as his comedy and has campaigned on issues including civil rights,  the Vietnam War, economic reform and, anti-drug  He even ran for President of the United States in 1968  for the Freedom and Peace Party. And in 1990 he travelled to Tehran during the US Embassy Hostage Crisis to try to negotiate the hostages' release. He has also disputed the official account of the September 11 terrorist attacks on the US.