John Luebbers, 44, was charged after telling investigators he fired two shots and struck Principal Sam LaCara, 50, in the office at Louisiana Schnell Elementary School in Placerville, police said.
Luebbers told police that LaCara had fired him Wednesday just days after the two friends had gone golfing. School officials, however, said Luebbers had only been sent home for the day after the two had an argument about the district's selection of a new nighttime custodian.
Luebbers entered a not guilty plea during his arraignment Friday afternoon and was held without bail. Family members attended the hearing but did not address reporters outside.
Prosecutors filed a murder charge with intent to cause great bodily injury and death using a .357-caliber revolver. According to William Clark, chief assistant district attorney of El Dorado County, Luebbers faces a maximum sentence of 50 years to life if convicted.
His next court appearance was scheduled for early March.
David Weiner, an attorney and friend of Luebbers' family, said the suspect was not in good health when he visited him in jail.
"He has medical problems. He suffers from some extreme diabetic problems and associated high blood pressure," Weiner said. "He's not in good shape at all."
No children were hurt in the attack, but police said one student may have witnessed the shooting about 50 miles east of Sacramento.
Placerville Union School District Superintendent Nancy Lynch said Thursday that LaCara had sent Luebbers home for the day after the janitor became upset over a personnel matter. Vicki Barber, superintendent of the El Dorado County Office of Education, said the two men apparently had a dispute about the nighttime custodian.
"Mr. LaCara thought he needed to go home and cool off for the day," Lynch said.
Students returned to school Friday for the first time since the shooting that prompted a lockdown of the 400-student campus. The school district had counselors on hand.
A memorial service for LaCara has been scheduled for Tuesday at a Placerville church. A makeshift memorial was set up at the school entrance following the shooting. Residents had gathered the night of the shooting to mourn LaCara, a married father of three daughters.
LaCara's brother-in-law, Guy Clark, told reporters Friday that the family is devastated, especially LaCara's wife.
"They were totally in love," Clark said. "She's crushed."
School district officials described LaCara as a beloved educator who got his start as a gym teacher and worked his way up to principal in 2003.
"Sam had an extensive network of friends and colleagues who affectionately called him 'the mayor,'" the district wrote in a statement. "This affectionate title referred to the way Sam knew how to get things done in ways to benefit the students he served."