A per diem attorney is a freelance attorney and independent contractor. A per diem attorney appears in varied courts on behalf of law firms who are the "attorneys of record" for a client on a given legal matter.
The per diem attorney is provided with information and specific instructions by the handling attorney and attorney of record. The matter and court appearance is handled in accord with the attorney of record's instructions.
The per diem attorney's appearance in court is strictly limited to the particular appearance made and the handling attorney remains responsible for the matter at all times.
Per diem attorneys usually only appear in one courthouse or one courtroom on a given date.