Layperson

[Guest Karen Judson]

Can a priest function as a priest without being under a bishop?

[truthfinder]

You've given no real details, but the short answer is: no.  Priests are to be incardinated into a diocese or are part of a religious order.  Even if they are 'travelling preachers' or the like, priests have a bishop.  From this bishop they receive their faculties: to say Mass, to preach, and to hear confessions.  These faculties are usually given together, but they can be separated (such as they can say Mass but not preach).  In emergencies, any priest can hear the confession of those who are dying - this includes those who have left the priesthood and have been returned to the lay state (canonically).  Outside of this, any priest who is functioning outside of a bishop's control is acting at the very least illicitly, and in many cases invalidly.  For instance, a priest performing marriages outside of the regular control of a bishop, would not be validly conducting these marriages and the marriages themselves would not be valid (although they might still be legally binding depending on the state).  

[Basilisa Marie]

Canonically, a priest usually functions as an extension of the bishop's ministry. The reason why we have priests is because the bishop can't be everywhere at once. Even priest who aren't part of a diocese are members of an order with someone at the top who functions like a bishop. A priest's "powers" must be exercised with the authority of the bishop he answers to, and/or the one who's in charge of the area.