The Desperate Housewives star admitted to paying $15,000 (£11,500) to have her daughter's exam answers secretly corrected in 2017.
She must also do 250 hours of community service and pay a $30,000 fine.
Parents and athletics coaches were among 50 people charged in the scheme, but none of the children were indicted.
"There are no excuses or justifications for my actions. Period," Huffman said in a statement after her sentencing. "I would like to apologise again to my daughter, my husband, my family and the educational community for my actions.
