The New Jersey Constitution of 1947 (Annotated) Art. V, § I, ¶ 6

6. In the event of a vacancy in the office of Governor resulting from the death, resignation or removal of a Governor in office, or the death of a Governor-elect, or from any other cause, the Lieutenant Governor shall become Governor, until a new Governor is elected and qualifies.

In the event of simultaneous vacancies in both the offices of Governor and Lieutenant Governor resulting from any cause, the President of the Senate shall become Governor until a new Governor or Lieutenant Governor is elected and qualifies. In the event that there is a vacancy in the office of Senate President, or the Senate President declines to become Governor, then the Speaker of the General Assembly shall become Governor until a new Governor or Lieutenant Governor is elected and qualifies. In the event that there is a vacancy in the office of Speaker of the General Assembly, or if the Speaker declines to become Governor, then the functions, powers, duties and emoluments of the office shall devolve for the time being upon such officers and in the order of succession as may be provided by law, until a new Governor or Lieutenant Governor is elected and qualifies.