There are not necessarily strict requirements for eligibility for a pardon in Pennsylvania. As long as a petitioner complies with the Board of Pardons' application process, they would be in most instances eligible to seek a pardon. That being said, it does not mean that everyone is appropriate to seek a pardon in Pennsylvania. It can be regarded as a general rule of thumb that a person should wait at least five years from the time that their case has come to a complete end before they apply, although it's not a requirement. The more time that passes from the time that the case is over and done with, the more time that a person would be able to show that they've reformed themselves so that's a consideration.
The Board of Pardons will take into account the totality of the person's circumstances. They'll consider the original offense and everything the person's been doing since that time to determine if it's appropriate to grant that person a hearing before the Board of Pardons. Although there's not necessarily any strict requirements, some people are definitely going to be more qualified to seek a pardon than others. Experienced Pennsylvania criminal defense attorney will be able to help you understand and navigate the process and be able to help you understand if you're appropriate for seeking a pardon and how to best go about doing so.