A spokeswoman said Christie cited time constraints for the decision, noting the many "pressing issues" the state is facing. However, the first-term Republican will retain his seat on the NGA's nine-member executive committee.
Democrat Delaware Gov. Jack Markell has taken over as chairman and Republican Oklahoma Gov. Mary Fallin was selected Sunday to serve as vice chair.
Besides his work as New Jersey's chief executive and the NGA, Christie also serves as a surrogate for presumptive GOP presidential nominee Mitt Romney and as vice chairman of the Republican Governors Association.
NGA members include the governors of the 50 U.S. states, three territories and two commonwealths.
