Jon Aleczander Sweet, 25, pleaded not guilty to three charges of unlawful sexual intercourse during a Kern County court hearing Wednesday.
Police said Sweet and the girl have had a sexual relationship for nearly three months. Sweet was also found in possession of several nude photographs of the girl, police said.
The judge said Sweet is not allowed to make contact with the victim or the victim's family. He's being held on $72,500 bail and will be due back in court in May.
Police announced the arrest on Tuesday, and the Diocese of Fresno soon followed with confirmation that Sweet, listed as "Alec Sweet" on the school's website, is a staffer at Garces.
Police didn't release information on how the man and girl met.