Thomas turned 89 years old on Tuesday. The president turned 48.
Mr. Obama brought cupcakes into the briefing room as reporters were preparing to question press secretary Robert Gibbs. He told Thomas that he would leave it up to her to decide how to distribute the cupcakes.
Thomas, a liberal columnist with Hearst Newspapers, made a wish and blew out a candle.
Mr. Obama said Thomas had wished for "world peace [and] no prejudice."
"But she and I also shared a common birthday wish: She said she hopes for a real health care reform bill," he added.
The president then gave Thomas a kiss and left the briefing room.