[3] The family moved to East Orange, New Jersey during Carter's high school years, where Carter's activism began after he read that a state court had ruled against racially discriminatory practices such as that high school's only allowing black students to use the swimming pool on Fridays, and entered the pool with white students, defying a teacher's threats.

Experiences such as a white captain's welcoming him to the Augusta, Georgia station by telling him that they did not believe in educating black people, made Carter militant.

[10] Nonetheless, Carter argued and won NAACP v. Button (1963), in which the Supreme Court struck down a Virginia statute restricting public interest litigation.

[9] Like NAACP v. Alabama, the Button decision eliminated a tool of massive resistance employed by some Southern states in response to Brown, and applied the First Amendment theories Carter began developing as a student at Columbia Law School.

[9] He served as a member of numerous bar and court-appointed committees, and was associated with a very wide array of educational institutions, organizations and foundations.

[citation needed] In 1968, Carter, along with his entire legal staff, resigned in protest from the NAACP after the organization fired attorney Lewis M. Steel for criticizing the Supreme Court in a The New York Times Magazine piece.

[13] Carter then worked at Columbia University's Urban Center, and joined the New York law firm of Poletti, Freidin, Prashker, Feldman & Gartner.

[citation needed] Carter also handled cases involving discrimination against black and Hispanic applicants to the New York City police force.

[citation needed] In 2005, Carter published a memoir of his experience as a civil rights advocate, A Matter of Law, with a preface by historian John Hope Franklin.