Dr. Atlas, Trump’s coronavirus adviser, resigns.

Dr. Scott W. Atlas, the former Stanford University radiologist who espoused disputed theories and rankled government scientists while advising President Trump on the pandemic, has resigned his White House position, according to a senior government official.

The move was not entirely unexpected. Dr. Atlas caught Mr. Trump’s eye with his frequent appearances on the Fox News Channel over the summer, and joined the White House in August as a special government employee for a limited term that was set to expire this week. Fox News first reported his resignation, which Dr. Atlas later announced on Twitter.

“I worked hard with a singular focus — to save lives and help Americans through this pandemic,” Dr. Atlas wrote in a letter obtained by Fox, adding that he “always relied on the latest science and evidence, without any political consideration or influence.”

But some of Dr. Atlas’s administration colleagues would likely differ with that assessment, citing views that differ starkly from those put forth by officials at the Centers for Disease Control and Prevention and other government scientists. Dr. Atlas has argued, for example, that the science of mask wearing is uncertain and that children cannot pass on the coronavirus.

Even more controversial was his libertarian vision of the role of the government in the pandemic. In Dr. Atlas’s view, the government’s job was not to stamp out the virus but simply to protect its most vulnerable citizens as Covid-19 takes its course.

His argument was that most people infected with the virus would not get seriously ill, and at some point, enough people will have antibodies from Covid-19 to deprive the virus of carriers — “herd immunity.” Public health experts were appalled, and Dr. Atlas clashed in particular with Dr. Anthony S. Fauci, the government’s top infectious disease specialist, and Dr. Deborah L. Birx, the coronavirus response coordinator.

“I don’t want to say anything against Dr. Atlas as a person, but I totally disagree with the stand he takes. I just do, period,” Dr. Fauci said earlier this month on the NBC program “Today.”

But Dr. Atlas had the ear of one person who mattered: Mr. Trump.