Joyce Hardin Garrard held hands with her defence lawyer as Etowah County Circuit Judge Billy Ogletree handed down the sentence on Monday.
Savannah Hardin collapsed after running and died three days later in 2012. Prosecutors said Garrard made the child run for hours as punishment for a lie about sweets.
The 50-year-old grandmother denied that she meant to harm the child. She told jurors the girl was running as practice because she wanted to do better in a race at school.
The jury that convicted Garrard recommended life in prison but the final decision was up to the judge.