Dr Sean Conley said the president had responded “extremely well” to medication and had “remained stable”.
The Centers for Disease Control and Prevention (CDC) in the US says that someone who has tested positive for the virus should self-isolate for 10 days – for Mr Trump this would be Saturday 10 October.
Mr Trump said he would probably take another coronavirus test on Friday claiming on TV that he was “a perfect physical specimen” and he hoped to hold a rally over the weekend.
Although his doctor has said he now has no symptoms, questions still remain about when the president first became infected and whether he could still be contagious.
The most powerful opposition politicians in Washington Democrat House Speaker Nancy Pelosi said serious questions concerning Mr Trump’s health were still unanswered and she wanted a commission – or investigation – to assess the president’s fitness for office and “help ensure effective and uninterrupted leadership”.
The President was first diagnosed with the virus on Thursday 1 October and was flown to a military hospital on Friday 2 October.
On Thursday evening, an official note from Dr Conley said Mr Trump was displaying no signs “to suggest progression of illness”.
“Saturday will be day 10 since [last] Thursday’s diagnosis, and based on the trajectory of advanced diagnostics the team has been conducting, I fully anticipate the president’s safe return to public engagements at that time,” the memo added.
Earlier, Dr Conley said that if the president’s condition remained the same or improved throughout the weekend and into Monday, “we will all take that final, deep sigh of relief”.