Just being charged (not sure if that means arrested, cited or you've actually been charged by the DA) doesn't mean you'll be convicted. There may be factual defenses, legal defenses or other alternatives to avoid a conviction. It sounds as though you haven't been to court yet, so you would do well to consult with a local criminal defense attorney to discuss your options.
Regarding your background check: The police can be quite thorough in their background of potential officers. This is going to come up. Your best bet is to try and avoid a conviction with the help of your attorney, disclose it when applying and don't have any further glitches or reasons for them not to hire you.
The above answer is for general information only and is based on the information you posted. Every case is fact dependent, so to get a thorough analysis of your situation, you will need to consult face to face with an attorney licensed to practice in the jurisdiction where the incident took place. Do not conclusively rely on any information posted online when deciding what to do about your case.
As a misdemeanor, if you are convicted, you will have it on your criminal record. However, how crimes are cited by police and how they are filed by the OCDA, are entirely different. Could very well be probation and a fine, but best to get an attorney to represent you.
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