Portland’s director of health and human services, Doug Gardner, is leaving after nine years on the job.

Gardner has accepted a position as vice president of operations at North Country Associates, a Lewiston-based company that operates nursing and assisted-living homes in Maine and Massachusetts.

Julie Sullivan, director of the public health division within Portland’s Health and Human Services Department, will fill Gardner’s position while the search for a new director is conducted, city officials announced in a news release.

“Doug’s passion and understanding of the issues surrounding health and human services in Maine has made him an excellent advocate for the residents of Portland,” City Manager Mark Rees said in a statement.

Gardner, who has worked for the city for 15 years, listed among his proudest accomplishments a program that aims to place homeless individuals and families in permanent housing, helping to reduce demand on the city’s homeless shelters.