Authorities found Kardos, 54, shortly before 11 a.m. His injuries appeared to be self-inflicted and there was no indication of foul play, Fairfield Fire Marshal Morgana Yahnke said.
Emergency personnel transported Kardos to NorthBay Medical Center where he was pronounced dead, according to Yahnke.
Kardos was scheduled to be sentenced Oct. 31 in Solano County Superior Court and faced three years and six months in prison, although his attorney Daniel Russo has said the councilman could have "reasonably" expected probation.
Kardos was arrested Jan. 20, 2007 for allegedly choking his ex-girlfriend, a 55-year-old Fairfield woman, the night before.
He was placed on paid administrative leave from his job as assistant principal at Armijo High School in Fairfield. He remained on the City Council but would have lost his seat and his job at the high school because he had been convicted of a felony, Russo said.
Kardos most recently worked at the Fairfield-Suisun Adult School in the administration department of the Independent Studies Program, Yahnke said.
Kardos was elected to a four-year term on the Fairfield City Council in November 2005, Yahnke said.
Kardos was also actively involved with was the "Matt Garcia Teen Center," scheduled to open in October following the Labor Day murder of 22-year-old Garcia, another Fairfield city councilmember, according to Yahnke.