Joe Biden intermittently coughed his way through a virtual White House meeting, a day on from his testing positive for COVID.
Mr Biden, who at 79 is the oldest person ever to serve as US president, appeared in good spirits but had a noticeably deeper voice and apologised for repeatedly breaking away from his speech to cough.
"I'm feeling much better than I sound," the president said, as he described recent efforts to lower US petrol prices.
It came after Chinese President Xi Jinping wished his US counterpart a speedy recovery in an official message.
Earlier on Friday, the White House doctor had released a statement saying Mr Biden's symptoms had improved.
The letter, released from physician Kevin O'Connor, said Mr Biden had a slight temperature of 37.4C (99.4F) but was responding "favourably" to painkillers and that he was breathing normally.
"His voice is deeper this morning. His pulse, blood pressure, respiratory rate and oxygen saturation remain normal, on room air," he said.
The doctor, who the White House said is seeing Mr Biden and checking his "vital signs, multiple times a day", added the two medicines he takes for atrial fibrillation (an irregular heart rate) and cholesterol were being held back temporarily to avoid interfering with his treatment course of an antiviral drug to help combat COVID.
He said low-dose aspirin was also being added as an alternative blood thinner.
"The president is tolerating treatment well," he said.
White House COVID-19 coordinator Dr Ashish Jha said Mr Biden was doing fine and his mild symptoms were basically the same - a runny nose, fatigue and occasional dry cough.
He added: "The president is doing better. He slept well last night. He ate his breakfast and lunch, fully. He actually showed me his plate."
The president, who is fully vaccinated and twice boosted, tested positive for the coronavirus on Thursday, when the White House said he would continue working but in isolation.
His diagnosis comes as a highly contagious subvariant drives a new wave of cases in the US, and as new figures released on Friday show infections in the UK have risen again to nearly 3.8 million.
US COVID cases have jumped more than 25% in the past month, according to data from the Centers for Disease Control and Prevention (CDC), as the new BA.5 Omicron subvariant takes hold there and across the world.