The jury, made of six women and six men, took about five hours to make their decision on Thursday.
Prosecutors say 49-year-old David Viens confessed that he bound his 39-year-old wife Dawn with tape, later found her dead, and then cooked the body for four days to dispose of it in October 2009.
Viens had pleaded not guilty, saying he didn't mean to kill her. He said binding her in tape was something he had done before to prevent her from driving under the influence.
The trial relied heavily on recorded interviews with authorities in which the chef acknowledged the crime and outlined his actions in detail.
"I just slowly cooked it and I ended up cooking her for four days," Viens could be heard saying on the recording.
Viens said in the interview that he stuffed his wife's body in a 55-gallon drum of boiling water and kept it submerged with weights. He said he mixed the remains after four days with other waste, dumping some of it in a grease pit at his restaurant in Lomita, and putting the rest in the trash.
Viens, a former chef and owner of Thyme Contemporary Cafe, jumped off a cliff in Rancho Palos Verdes in March 2011 when he learned he was about to be arrested. He was injured but survived the 80-foot fall. He appeared in court in a wheelchair when the verdict was read.
Viens will be sentenced on Nov. 27. He faces 15 years to life in state prison.
The Associated Press contributed to this report.