The 48-year-old former first baseman with the Diamondbacks and the Chicago Cubs pleaded guilty on Jan. 31 to felony endangerment and misdemeanor driving under the influence of alcohol.
He began his sentence on Feb. 10 in Maricopa County's outdoor Tent City. He was released Monday and must also serve two years of probation.
Grace was arrested last August in Scottsdale, his second DUI arrest in 15 months. Police say he was driving without an interlock device in violation of his probation.
The Diamondbacks later fired him as their analyst after nine seasons with the team, but Grace was later rehired as a minor-league coach and instructor.