If I were you, my long term goal would be to get myself set up with my own consulting company. It will help to separate your personal history from your work history. Companies don't have felony convictions.
Actually, it may. If someone runs a background check and sees a sealed record, it tells them that a record exists, but not the nature of the offense. They would probably therefore assume something worse than a marijuana conviction, which is what OP has.
This may vary by state based on what information remains available, but sealing the record MAY actually be worse than leaving it open.
Obligatory: IANAL.
Edited wording to clarify that this is a hypothetical employer, not what I myself would do personally.
...sigh. That just makes it worse for those of us that try to move on past our mistakes.