Seale joined the African American Association in college which lead to the forming of the Black Panther Party. Seale went on to become the chairman of the party and underwent FBI surveillance as part of its COINTELPRO program. He was one of the original Chicago Eight defendants charged with conspiracy and inciting to riot, in the wake of the 1968 Democratic National Convention, in Chicago. Judge Julius Hoffman sentenced him to four years of imprisonment for contempt of court because of his outbursts, and eventually ordered Seale severed from the case, hence the "Chicago Seven." During one of the court trials Bobby Seale's many outbursts led the judge to have him bound and gagged.
Seale was also tried in 1970 in the New Haven Black Panther trials for the murder of Alex Rackley and acquitted by a hung jury. Radical students at Yale University, including Hillary Clinton, protested in support of Seale and the Black Panthers.