The Vicar General is a priest who assists the diocesan bishop in the governance of the whole diocese. He is ‘the pre-eminent official of the diocesan curia’.
The priest appointed to this office is to be over thirty years of age, with a doctorate or licentiate in canon law or theology, or well versed in these disciplines, and be known for his soundness of doctrine, integrity, prudence and practical experience.
As a Vicar, this priest acts in the name of the Bishop. As Vicar General, he possesses, by virtue of his office, the same executive power throughout the whole diocese as that which belongs by law to the diocesan bishop.
Provided that the Vicar General is not the coadjutor bishop or an auxiliary bishop, the Vicar General ceases exercising office when his term of appointment has expired and this has been communicated in writing, or when he has been removed from office, or when the see is vacant.
Church Administration Handbook, pg 142