Dixon was born in Washington D.C. and served in the United States Army from 1957 to 1960. He graduated from California State University, Los Angeles in 1962. He was elected to the California State Assembly as a Democrat in 1972, and served in that body for three terms. Dixon was elected to the House of Representatives in 1978. He chaired the rules committee at the 1984 Democratic National Convention and the ethics probe into Speaker Jim Wright. Dixon won re-election to the 107th United States Congress, but died of a heart attack in December 2000.
The third revised edition of Black Americans in Congress 1870-2007 (House Document 108-224, Serial Set v.14904) is dedicated to the memory of Dixon. Remarks requesting this were made by several of his colleagues March 21, 2001 on the House floor during consideration of House Concurrent Resolution 43 of the 107th Congress which ordered the printing of the revised edition.
The busy 7th Street / Metro Center / Julian Dixon transfer station for the Red Line, Purple Line, Blue Line and Expo Line in downtown Los Angeles is named after Dixon, with a plaque commemorating his role in obtaining the federal funding that enabled construction of the Metro Rail system. His alma mater, Southwestern University School of Law, in 2004 opened the Julian C. Dixon Courtroom and Advocacy Center in the former Bullocks Wilshire building. The Culver City branch of the Los Angeles County Library is also named in his honor, Culver City Julian Dixon Library.