Kennedy was born in Sacramento, California. He married Mary Davis and has three children. He received his B.A. from Stanford University and the London School of Economics, and his LL.B. from Harvard Law School. He was in private practice in San Francisco, California from 1961-1963, as well as in Sacramento, California from 1963-1975. From 1965 to 1988, he was a Professor of Constitutional Law at the McGeorge School of Law, University of the Pacific. He has served in numerous positions during his career, including a member of the California Army National Guard in 1961, the board of the Federal Judicial Center from 1987-1988, and two committees of the Judicial Conference of the United States: the Advisory Panel on Financial Disclosure Reports and Judicial Activities, subsequently renamed the Advisory Committee on Codes of Conduct, from 1979-1987, and the Committee on Pacific Territories from 1979-1990, which he chaired from 1982-1990. He was appointed to the United States Court of Appeals for the Ninth Circuit by President Ford in 1975. President Reagan nominated him as an Associate Justice of the Supreme Court, and he took his seat February 18, 1988.