Mr Trump is for a summit marking the 70th anniversary of the Western military alliance.
In addition, he stated he can see France”breaking off” out of Nato, but didn’t explain why.
The 29 member states pledge to come to the help of one another should any come under attack.
But last month, Mr. Macron whined that Nato members were on crucial issues.
He described the alliance as”brain dead”, stressing what he saw as a waning commitment from its main guarantor – the US.
The summit, due to getting underway later on Tuesday, has been overshadowed by a bitter row between member states France and Turkey, and a continuing disagreement over money.
President Recep Tayyip Erdogan has said he’ll oppose Nato’s plan for the defense of the southern region if it doesn’t back Turkey over its struggle against Kurdish classes.
Working alongside Nato Secretary-General Jens Stoltenberg at a press conference, President Trump said Nato”serves a fantastic purpose”, but was then asked what he thought about Mr. Macron’s statements.
He said he believed the French leader was”very disrespectful” to other alliance members.
“It is a very, very horrible statement. I believe they have a large unemployment rate in France. France isn’t doing well economically at all,” he explained.
“It is a very tough statement to create when you have such difficulty in France if you take a look at what is happening. They’ve had a rough year. You just can’t go around making statements. It is extremely disrespectful.”
He added: “Nobody wants Nato more than France… that the US advantages the least. For them to create it’s an invoice.
“I’m considering him [Mr. Macron] and I’m stating that he needs protection more than anybody, and I see him breaking off [from Nato]. So I am a little surprised at that.”
Mr. Erdogan had earlier joined the dispute, indicating that Mr. Macron was the one who had been”brain dead” and accusing him of having”a sick and shallow comprehension” of terrorism.
Mr. Trump also reiterated his longstanding criticism that many Nato countries were not contributing fiscally.
Mr. Stoltenberg praised Mr. Trump’s”leadership on defense spending”, saying it had been having a real effect.
“Since 2016, Canada and European allies have added $130bn more to the defense budget, and this number increases to $400bn from 2024,” he said.
“This is unprecedented, this is making Nato stronger, and it demonstrates that this alliance is adapting, responding when the planet is shifting .”
The extra spending was welcomed by President Trump singled out Germany as falling short. According to Nato’s newest figures, Germany spends 1.36percent of GDP on defense as soon as the Nato guideline is 2%.
On a more positive note, he added: “The world has changed a great deal and Nato is shifting right now. I’ve come to be a fan of Nato because they’ve become more flexible.”
Ahead of his departure for London, Mr. Erdogan said Turkey would not approve a plan to shield Poland, Lithuania, Latvia, and Estonia in the event of an attack unless the Kurdish YPG militia was recognized by Nato as terrorists.
The YPG directs the Allied Democratic Forces (SDF), key allies of the US-led coalition from the Islamic State group in Syria. In October, Turkey launched an operation in Kurdish-controlled regions of northern Syria to create a”safety zone” along its boundary.
“If our buddies at Nato don’t recognize as terrorist organizations those we believe terrorist organizations… we’ll stand against any measure which will be taken there,” he explained about the plan.
That action took place after President Trump pulled US forces from the area without consulting allies, also deepened cracks between other Nato members and Turkey.
Mr. Macron and Mr. Erdogan will come face to face in a four-way meeting including the host, UK Prime Minister Boris Johnson and German Chancellor Angela Merkel in Downing Street on Tuesday.