Depending on the depth of the background check, it could be discovered that you had been convicted of a misdemeanor that was reduced to an infraction. However, how deep an employer will go with a background check will be a function of the kind of employer, the nature of your job and the motivation of the employer to find background information.
Whether it would bar employment is also a question that can only be answered by the person making the hiring decision. There are no hard and fast rules applied across the board by all employers about what will and will not disqualify and employee.
You can run a basic background check on yourself. There are several services that will do that for you. Just Google it to find several of those companies, many of which are used by employers.
Good luck to you.
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