It will seal but when it seals depends on what your sentence was. If you did anything that required a Conditional Discharge such as community service, it will not seal until 1 year after the sentence date. If you just paid a fine (not the court surcharge) it will seal upon payment.
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It should be sealed 1 year after your plea but the arrest often still shows up in which case you may have have to pay a criminal lawyer a small fee to have it expunged.
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My colleagues give you good advice, but please keep in mind that certain high level background checks such as for Federal employment are likely to turn up even a sealed disorderly conduct.
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