N.J. Stat. § 30:9-23.1
Whenever a city of the first class has established or establishes a city hospital or medical center with a capacity of more than one thousand beds and the said city of the first class is located in a county of the first class which has established or establishes hospitals and institutions rendering medical care, the governing bodies of the county and municipality, in the management of their respective hospitals may jointly agree to appoint a medical director who shall have supervision over all the county and municipal hospitals, centers, or institutions which render medical treatment or care to patients, a supervisor of nurses, a purchasing agent and any other persons as said governing bodies may deem necessary in order to render joint service to the county and municipal hospitals, centers or institutions, and may make and enter into any joint contracts for the maintenance or proper repair of the buildings, facilities and equipment thereof and for the furnishing of material and labor. The said governing bodies shall fix or regulate the salaries to be paid, determine the proportion to be paid by the county and the municipality and shall have the power to make any and all other necessary agreements and contracts to carry out the purposes of this act. The person so appointed as medical director shall have the following qualifications: he must be a graduate of a recognized medical college, holding a diploma therefrom; must be admitted to practice as a physician, and must have been practicing medicine or associated with medical institutions, or both, for a period of at least fifteen years.
N.J.S. § 30:9-23.1