The verdict came after a five-month trial of the members of MS-13, or La Mara Salvatrucha, who prosecutors said waged war with rival gang members in the city's Mission District.
"Today's verdicts should send a strong message to anyone who thinks gang membership gives them the power to intimidate, threaten, steal or kill," U.S. Attorney Haag said in a news release. "Acts of senseless violence will not be tolerated."
Among other charges, Erick Lopez, 23, was convicted of the fatal shootings of Ernad Joldic and Phillip Ng in March 2008. Guillermo Herrera and Jonathon Cruz-Ramirez, both 22, were convicted of the July 2008 racketeering murder of Armando Estrada.
Marvin Carcamo, 31, and Angel Noel Guevara, 30 -- who led the gang in 2007 until their arrests late that year -- were linked to the May 2, 2007, murder of David Pollock in San Francisco, and the murder weapon was found at Carcamo's home, prosecutors said.
Lopez, Herrera and Cruz-Ramirez each face a mandatory minimum of life in prison.
Moris Flores, 22, who was leader of MS-13 after the arrests of Carcamo and Guevara, was involved in Lopez's hunt for rival gang murders, which led to the murder of Ng and Joldic, prosecutors said.
A seventh defendant was acquitted.