When you are convicted of a misdemeanor, the court will normally impose a period of informal probation. This period can be for 1, 2 or even 3 years. Generally, the purpose of probation is to give the court the authority to enforce the terms of your sentence. For instance, lets say you are convicted of a DUI - driving under the influence of alcohol or drugs. The standard sentence for a first time DUI involves a fine, some classes and set of standard alcohol conditions. In exchange to accepting these terms, you don't have to spend any more time in jail. To make sure you live up to your end of the bargain, the court imposes probation. If you fail, then the court will revoke your probation and potentially send you to jail. Once you have completed your classes and paid your fine, some judges will terminate your probation early. Otherwise, you will have to wait until the period ends. A criminal defense lawyer can prepare and file a motion to encourage early termination.
File a Petition for Relief
You can download and fill out the court approved form to petition for relief (link below). Make a copy for yourself and file the completed form at the court house where your case was originally heard. If you have moved, you can mail the form or hire an attorney to complete the form and file it on your behalf. You will likely need to pay a $60 court processing fee at the time the form is filed.
For misdemeanors, generally no hearing is required. The court will notify you or your attorney in 4 to 8 weeks of the status of your petition. If your petition is granted, then your conviction will be vacated and the charges against you will be dismissed. If your petition is not granted, you can reapply as many times and as often as you like. You'll have to pay a fee each time. To increase your odds of success on a subsequent application, you should hire a lawyer to prepare your petition and supplement it with a detailed motion explaining why expungement is particularly appropriate in your case.
Recognize the Limitations of Expungements
Once your misdemeanor is expunged, the rest of the world should treat you as if you had never been convicted. Unfortunately there are some limitations. First of all, if you get a DUI expunged, your next DUI will still be treated as a 2nd DUI - with the same significant sentence enhancements imposed as if you did not get the 1st DUI expunged. Anyone who gets a copy of your California Department of Justice background report will see the original conviction. Following the entry for your conviction will be a line stating that your conviction was vacated and the charges were dismisssed per PC1203.4. Some employers will never see this report, and others are legally bound to treat you as if the conviction happened. However, if you are attempting to get a job as a peace officer or government agent, expungements are generally not recognized. Good luck.