The decision, made by a 4-1 vote, may be overridden by a two-thirds vote of the City Council.
"The department is suffering a profound loss of confidence. Today the Los Angeles Police Department is in crisis," said Caruso, president of the civilian commission. The bid by Parks, the city's second black police chief, was opposed by Mayor James Hahn, whose powers include appointing police commissioners.
Hahn was elected last year with the support of the police union and the black community. Many black leaders denounced Hahn when he announced this year that he wanted a new chief.
Parks, 58, was selected as chief in 1997 by then-Mayor Richard Riordan and enjoyed broad support in the City Council. The 37-year police veteran also earned praise from many civil rights leaders for increasing officer discipline.
There were hopes that Parks, a veteran of the department's internal affairs division, could restore a department tarnished by the King beating, the 1992 riot and the mishandling of the O.J. Simpson murder investigation.
But Parks quickly got into trouble with the Los Angeles Police Protective League.
The 8,300-member union issued a no-confidence vote in January, saying 93 percent of responding members did not support Parks. The union, which opposed Parks' original appointment, claimed his approach to discipline was harsh, lowered morale, and drove officers away. The force is about 1,100 officers below its mandated strength of 10,000.
Parks also opposed a federal consent decree on police reforms that Hahn supported.
The U.S. Justice Department began investigating allegations of civil rights abuses and use of excessive force by police officers in 1995 and the probe was quickened when corruption among Rampart Division anti-gang officers surfaced in 1999.
Hahn was elected last year with the support of the police union and the black community. Many black leaders denounced Hahn when he announced this year that he wanted a new chief.
The commission, a civilian panel that oversees the Police Department, voted after setting performance evaluation criteria and holding public and private hearings.
The process was put in place immediately after the 1992 riot, when voters approved a City Charter change that stripped the chief's position of civil service protection and limited chiefs to a five-year term, renewable once at the commission's discretion.
The change was a key recommendation of the special Christopher Commission, which examined the department after the 1991 Rodney King beating and urged increased accountability by chiefs.