Attorney for radical and sometimes controversial figures like the Chicago Seven, Martin Luther King, Jr., and Colin Ferguson, who shot six people to death.
As a teenager he ran around committing petty crimes with a gang called The Red Devils.
He enjoyed defending the unpopular partly because of the publicity he got from it, and partly, he said, because he didn't want the state to become all-powerful.
He had four children with his wife, and two of his daughters, Emily Kunstler and Sarah Kunstler, made a documentary about him entitled William Kunstler: Disturbing the Universe.
He became renown for defending Abbie Hoffman and the Chicago Seven in a trial that became half farce due to his sharp exchanges with the judge and the antics of the defendants.