Dixon died of an apparent heart attack, Democratic aides said Friday. Rep. Charles Rangel, D-N.Y., said Dixon had recently informed his colleagues that he was undergoing minor surgery. He was 66.
A strong advocate of civil rights causes, Dixon's legislative career also covered a broad range of subjects ranging from intelligence, defense, congressional ethics and federal management of the District of Columbia.
"I've never known a more gentle, conciliatory, wonderful human being than I've known in Julian Dixon," said House Democratic leader Dick Gephardt of Missouri, who led a somber procession of lawmakers to the House floor to pay tribute to Dixon.
Dixon was the ranking Democrat on the House intelligence committee and a key member of the panel that determines defense spending, a position he used to promote federal aid for communities hit by base closings and other defense cuts.
He was also known for his efforts to boost the economic standards of his district and maintain the nation's commitment to civil rights.
Dixon was long regarded as Congress' leading supporter of Los Angeles' commuter rail system.
"Without Julian Dixon, there wouldn't have been a Metro Rail here," said Metropolitan Transportation Authority spokesman Marc Littman. "He's long been a champion of not just Metro Rail, but other transportation projects in Los Angeles ... He really led the charge to improve transportation."
Following the 1992 civil disturbances in Los Angeles, he moved to provide emergency funds for damaged businesses, and led efforts to help his community after the 1994 Northridge earthquake.
He chaired the Congressional Black Caucus in the 1980s and more recently worked to pass legislation to establish a memorial to Martin Luther King in the nation's capital.
"Steady as a rock. Dependable. Friendly. You could always go to him for help. He's loved in California. This comes as a great blow. I'm going to miss him," said Rep. Maxine Waters, D-Calif.
Dixon was born in Washington, D.C., in August 1934, and had long been involved in House panels that oversee federal funding for the nation's capitol. "He came to the defense of home rule, to the aid of the schools, health care, their police and fire departments. He felt a real responsibility and he discharged that responsibility with great humanity," said Fortney "Pete" Stark, D-Calif.
Dixon received a bachelor's degree in 1962 from California State University in Los Angeles and a law degree from Southwestern University in Los Angeles in 1967. He served in the Army from 1957 to 1960 and served in the California Assembly from 1972 until 1978. That year he was elected to the first of 11 terms in the House. He won re-election in November with 84 percent of the vot.
He is survived by his wife, Bettye Lee, and a son, Cary Gordon Dixon.