A third-generation Japanese American, Matsui was born in Sacramento, California and was six months old when he and his family were taken from Sacramento and interned by the U.S. government at the Tule Lake camp in 1942.
Matsui graduated from the University of California, Berkeley and Hastings College of Law. He founded his own Sacramento law practice in 1967 and was elected to the Sacramento City Council in 1971. He won re-election in 1975 and became vice mayor of the city in 1977.
In 1988, Matsui helped shepherd the Japanese-American Redress Act through Congress, in which the government formally apologized for the World War II internment program and offered token compensation to victims. He was also instrumental in the designation of Manzanar internment camp as a national historic site and in obtaining land on the National Mall in Washington, D.C, for the memorial to Japanese American patriotism in World War II.
He is married to the former Doris Okada, who is Senior Advisor and Director of Government Relations at the firm of Collier Shannon Scott, PLLC. Until December 1998, Doris Matsui worked as Deputy Assistant to the President and Deputy Director of Public Liaison for President Bill Clinton. The Matsuis have one grown son, Brian, who received his undergraduate and law degrees from Stanford University.