N.J. Stat. § 52:15-5
Whenever the functions, powers, duties and emoluments of the office of Governor shall have devolved upon the President of the Senate, the Speaker of the House of Assembly, for the time being, or any other person, other than the Lieutenant Governor, in accordance with the Constitution of this State, or laws adopted pursuant thereto, the official title of the person administering the Government of the State, for the time being, shall be "President of the Senate (or Speaker of the House of Assembly, or as the case may be), Acting Governor of the State of New Jersey." Said title shall be used in all legislative, executive and judicial proceedings or documents in which it is necessary to describe by his title the person administering the Government for the time being. The signature of the person administering the Government for the time being shall be in the following form: "A. B., President of the Senate (or Speaker of the House of Assembly, or as the case may be), Acting Governor," and the attestation to said signature shall be in the following form: "By A. B., President of the Senate (or Speaker of the House of Assembly, or as the case may be), Acting Governor."
However, the official title of a person who serves as Acting Governor for a continuous period of at least 180 days shall thereafter be, for all of the purposes of this section, as well as for all historical purposes, "Governor of the State of New Jersey." A temporary discontinuance of service as Acting Governor, due to travel outside of the State or inability to discharge the duties of office because of illness, shall not render a period of service noncontinuous.
N.J.S. § 52:15-5