Depends on the laws of your state and how the "public records search history" of your court operates. Some states allow courts to "purge" case files after so many years. Generally, this doesn't actually remove the criminal history--it just allows the court to destroy the physical file for record management purposes. There will still be a record of the arrest and outcome of the case with your state's Department of Justice.
Additionally, the court may still have the records but whatever search procedure/application you're using doesn't include the data. Courts do periodically change/update their systems, and it's not always possible or cost-effective to transport older data into the new system. However, someone contacting the court and/or DOJ for a proper background check will be given the correct information.
But it could also be that your state laws allow for the criminal record to "expire" and be removed entirely. The more serious the crime, the less likely this is the case (i.e., if it was an infraction it's entirely possible, but pretty much impossible if it was a felony).
As for whether or not an employer sees it, that'll depend not only on the above, but what type of job you're applying for. Unless it's relevant to the job, an employer usually won't waste the time or money on a criminal background check. But if you're applying for a job that deals with a lot of cash-handling, or security, or sensitive information, then a proper background check will probably be done and they'll probably see the criminal history.