Chris Knehans' guilty plea was for two counts of felony sexual misconduct involving a high school student.
The sexual contact incidents happened on two separate days in September 2011.
With Knehans' plea agreement this morning, he accepted a sentence of 30-60 days of incarceration for one of the sexual misconduct charges.
But a judge has to agree to that sentence and sentence the former teacher on the other count of sexual misconduct, where the punishment is up to four years in prison. A judge will make that decision in December.
By pleading guilty, Knehans avoids a jury trial that was set for Tuesday.
Knehans had already lost his job with Jefferson City schools and his teaching certification because of these charges.