BALTIMORE — Dr. Benjamin Carson was a political unknown just weeks ago.

Then with a single speech delivered as President Obama looked stonily on, he was lofted into the conservative firmament as its newest star: a renowned neurosurgeon who is black and has the credibility to attack the president on health care.

In his speech at the National Prayer Breakfast last month, Dr. Carson criticized the health care overhaul and higher taxes on the rich, while warning that “the P.C. police are out in force at all times.”

Overnight, he was embraced by conservatives including those at The Wall Street Journal editorial page, which proclaimed, “Ben Carson for President” — a suggestion Dr. Carson helped feed at a high-profile gathering last weekend, the Conservative Political Action Conference. He was interrupted by sustained cheers when he coyly said, “Let’s just say if you magically put me in the White House...”

In an interview in his office at Johns Hopkins University, he said he had been told for years that he could have a political career. It would be built on his compelling personal story that began in poverty in Detroit, leading to fame through pioneering work separating conjoined twins and his own self-help and inspirational books, including “America the Beautiful: Rediscovering What Made This Nation Great.”