Martin Albert Gallegos, 48, pleaded guilty last month to statutory rape. He also admitted an allegation that the victim, a senior, was not his spouse and was more than three years younger than him.
At sentencing Friday, Gallegos was placed on three years probation but won't be required to register as a sex offender.
The defendant was arrested April 9, one day after a campus police officer got a report about the crime, which occurred about a month earlier, said sheriff's Lt. Dan Brislin.
Gallegos had worked for the Sweetwater Union High School District since last fall, filling in periodically for full-time teachers, according to district spokesman Manny Rubio.