White House Names RFK Jr. Ally Jim O’Neill as Acting CDC Director After Sudden Firing of Susan Monarez

The White House has appointed Jim O’Neill, a top deputy to Health and Human Services (HHS) Secretary Robert F. Kennedy Jr., as the new acting director of the U.S. Centers for Disease Control and Prevention (CDC), following the abrupt removal of Susan Monarez.

Monarez, confirmed by the Senate just a month ago, was asked to resign after reportedly clashing with President Donald Trump’s health policy direction. When she refused to step down, the president dismissed her directly, a move confirmed Thursday by White House spokesperson Karoline Leavitt.

“She was not aligned with the president’s mission to make America healthy again,” Leavitt told reporters. “The secretary asked her to resign. She said she would, then she said she wouldn’t. So the president fired her — which he has every right to do.”

The leadership shake-up comes during a period of significant transition within the CDC, with the agency undergoing structural changes and budget cuts under Kennedy’s leadership.

Jim O’Neill, sworn in as HHS deputy secretary on June 9, will now take on CDC leadership in an acting capacity. His role at HHS includes oversight of several major federal health agencies, including the CDC, FDA, NIH, and CMS.

O’Neill previously served in HHS between 2002 and 2008, most notably leading FDA reforms in food safety and pharmaceutical regulation. He holds degrees from Yale University and the University of Chicago.

The fallout from Monarez’s firing has reportedly triggered additional resignations within the CDC, as multiple senior officials expressed concerns over the agency’s trajectory and the administration’s approach to public health policy.

Monarez, a microbiologist with a PhD, had been sworn in on July 31. Her brief tenure marked an attempt to stabilize the CDC during a time of mounting internal and external challenges.