His comments came after the country's top infectious disease expert, Dr Anthony Fauci, urged state and local leaders to be "as forceful as possible" in getting people to wear masks.
Wearing face coverings, Dr Fauci added, is "really important" and "we should be using them, everyone".
The wearing of face coverings has become highly politicised in the US.
The majority of state governors have now ordered that the wearing of masks outdoors be mandatory, rather than a personal choice. Among them are Republican governors, including Kay Ivey of Alabama, who have reversed their initial opposition to the mandates.
President Trump, who had previously resisted wearing a face covering himself, wore a mask in public for the first time last Saturday.
But speaking to Fox News on Friday, Mr Trump said he didn't agree with a national mask mandate, saying people should have a "certain freedom".
Earlier this week, US public health body the Centers for Disease Control and Prevention (CDC) released a statement urging everyone to wear masks.
"We are not defenceless against COVID-19," CDC Director Dr Robert R Redfield said. "Cloth face coverings are one of the most powerful weapons we have to slow and stop the spread of the virus - particularly when used universally within a community setting."