The Trump administration on Friday named Dr. Brenda Fitzgerald, the public health commissioner of Georgia, as the head of the Centers for Disease Control and Prevention, the nation’s top public health post.

Dr. Fitzgerald, who turns 71 next week, is an obstetrician-gynecologist and a two-time Republican congressional candidate. She has strong ties to two other prominent Georgia Republicans — Tom Price, the secretary of Health and Human Services, and Newt Gingrich, the former speaker of the House, who has been an informal adviser to President Trump.

Dr. Fitzgerald is a moderate, however, and is likely to come as a relief to those who feared Mr. Price would name a strong conservative to the post. Her appointment follows two other selections for key health posts that have been generally well received by Democrats: Mr. Trump’s nomination of Dr. Jerome M. Adams, a widely respected health commissioner for Indiana, to be the surgeon general; and the announcement that Dr. Francis S. Collins will remain as director of the National Institutes of Health, despite protests from conservative lawmakers.

Dr. Fitzgerald takes over the C.D.C. as the agency is grappling with a rising epidemic of opioid abuse; global outbreaks of infectious diseases such as Zika and Ebola; and an anti-vaccination movement with a sympathetic ear in Mr. Trump. It is also facing budget cuts: Mr. Trump has called for a 17 percent reduction in funding for both the C.D.C. and its sister office, the Agency for Toxic Substances and Disease Registry, which investigates environmental health hazards.