The 31-year-old country singer has been in jail since July, when she returned to Nashville after being accused of scratching her mother in a scuffle and resisting sheriff's deputies in her hometown of Fort Myers.
McCready received a suspended three-year sentence in 2004 for fraudulently obtaining prescription painkillers.
The singer sobbed as she asked for leniency from Circuit Judge Jeff Bivins.
"Your honor, I can honestly tell you this: This has been the longest two months of my life ... not being able to hold my son ... has been excruciatingly painful."
"I could only say I'm sorry," she said. "Please give me a chance to make things as right as they can possibly be."
Bivins sentenced her to a year in the county jail with credit for 75 days of time served. After her release she will face another two years of probation.
Deputy District Attorney General Derek Smith said McCready violated probation by being charged in a new offense, not reporting those charges immediately to her probation officer and by the nature of the new assault charges.
McCready had a hit in 1996 with "Guys Do It All the Time."
She has struggled with legal and personal problems that included a beating by her then-boyfriend and suicide attempts. She gave birth to her son in 2006.Still pending is a charge of violating her probation for driving on a suspended license in 2005.