Rudy Ruiz, 34, and John Perez, 47, were convicted in April of three counts of first-degree murder and seven counts of attempted murder in connection with the June 27, 2009, shooting at Falcone's Pizza.
At the time of the shooting, the victims were holding a fundraiser for a two children who had lost a parent in a house fire.
According to prosecutors, Ruiz and Perez, both gang members, mistakenly believed that the victims were members of a rival gang. Ruiz fired the first shots from the back of the crowded restaurant while two other gunmen waited outside the front, authorities said. Perez was the getaway driver, prosecutors alleged.
Garret Dandini, 25, Tony Dandini, 39, and Juan Carlos Carrera, 37, were killed. Seven others were injured, including one woman who must now use a wheelchair.
At Friday's sentencing, Helen Dandini spoke about her son, Garret, who served three tours of duty in Iraq and one in Korea and was working as a recruiter for the Navy at the time of his death.
"He loved what he did. This is why it is so hard for us to comprehend the fact he died by terrorists from his own country, the same country he was defending," said Dandini, who was joined at the podium by her husband, Hank.
Throughout the sentencing, Ruiz grinned at Dandini and her family, and at one point waved. Prosecutors said Ruiz frequently looked back and smiled at the victims' families during the trial.
"Yours is laughter of fear, ours is laughter of relief, and of justice, knowing that you ... can no longer hurt or destroy innocent victims' lives," Dandini told Ruiz and Perez during her remarks.
Get breaking news alerts delivered to your mobile phone. Text BREAKING to 52669. You will receive up to 30 msgs/mo. Msg&data rates may apply. Text HELP for help. Text STOP to cancel.
At least two other men were believed to be involved in the shootings. One suspected gunman was later killed, according to prosecutors, and the investigation into a second suspected gunman remains open.