Levar Haney Washington, 30, pleaded guilty to conspiracy to levy war against the United States through terrorism.
The prison-hatched conspiracy targeted the Israeli consulate and some of its officials, the El Al ticket counter at Los Angeles International Airport and two synagogues in the predominantly Orthodox Pico-Robertson neighborhood.
Also on the target list were U.S. military recruiting stations.
Members of the cell were three American-born converts to Islam - Washington, Gregory Vernon Patterson and Kevin Lamar James - and a Pakistani national, Hamad Riaz Samana.
According to the indictment, James founded the cell while in California state prison and named it Janiyyat Ul Islam Is Saheeh (JIS), roughly translated as the Assembly of Authentic Islam, an extremist offshoot of Louis Farrakhan's Nation of Islam.
The plot was discovered through a lucky break in July 2005, when Torrance police found a mobile phone dropped by Patterson while he and Washington were robbing a gas station to finance their operations.
The find led police to Washington's apartment, where they found "jihadist" literature, bulletproof vests, and a list that included the "headquarters of Zion" with the address of the Israeli consulate.
Some 200 local and federal agents of the FBI's Joint Terrorism Task Force participated in the subsequent investigation, with officials warning that "the conspirators were on the edge of launching their attack" - apparently on Yom Kippur.
Throughout the 2005 High Holidays, the Jewish community and law enforcement agencies were on high alert, with rabbis and lay leaders trying to strike a balance between maintaining security and avoiding panic.
Rabbi Abraham Cooper, associate dean of the Simon Wiesenthal center, urged prison officials on Monday "to ensure that terrorist groups are not able to recruit prisoners for their culture of death."
James and Patterson have also pleaded guilty and are awaiting sentencing. Samana was declared incompetent to stand trial and is confined to a hospital.