Eaton County Judge Thomas Byerley said Jason Algra violated the public's trust.
Algra was convicted in January of third-degree criminal sexual conduct with a 17-year-old boy, but was cleared of other charges involving a 15-year-old boy.
The former Grand Ledge High School teacher declined to speak in court Friday, but insists he's innocent. His maximum sentence is 15 years in prison, but he'll eligible for parole after five.
The judge told Algra that parents lose trust in the school system when teachers are convicted of sex crimes.