Gerald served in her post for 18 months.
In a resignation letter obtained by ABC11, Gerald lists her accomplishments on the job, but says she has had "significant differences and disagreements with many of the policy and administrative directions that I see unfolding in North Carolina."
Still, Gerald thanks the McCrory administration for allowing her to serve, but says she will now "need to do so in a different venue."
The Deputy Director of Public Health, Danny Staley, will serve as the acting director.
Robin Cummings, director of the agency's office of rural health and community care, will temporarily serve as acting state health director.
Former Gov. Beverly Perdue appointed Gerald in January 2012, when the agency merged its division of public health and office of rural health and community care.