And last week, the same day the donation was announced, the company -- Phantom Fireworks of Youngstown, Ohio -- got what it wanted: Trump decided to hold off on his threatened $300 billion in tariffs on Chinese goods, which include fireworks.
"This is another example of how private companies attempt use their money to influence the government by stroking the president's ego," said Jordan Libowitz with Citizens for Responsibility and Ethics in Washington, a nonpartisan watchdog group.
Company executives said the donation had been in the works for months and that the gift was not politically motivated.
The Interior Department, which is overseeing the event, declined to comment on its policy for vetting and accepting donations.
"While the donation of fireworks for D.C.'s Independence Day gala is generous and supported by many, it raises ethical concerns," said Scott Amey, general counsel of Project on Government Oversight, a nonpartisan, independent watchdog group. "The fireworks companies have reportedly lobbied against tariffs, and they could be using the Trump administration's celebration to better their business opportunities. We have witnessed a blurring of the line between government and business with this administration and things don't seem to be improving."
Phantom Fireworks CEO Bruce Zoldan told ABC News Live last month that he met face-to-face with Trump in May during an Oval Office meeting with business leaders to discuss the impact of tariffs, but he said that the group did not explicitly discuss fireworks.
"They were all sympathetic to what I was saying, but holding on to the fact that China needed to be punished for what they felt were predatory issues and unfair trade. And they said hopefully a deal will be made," Zoldan said.
China is the world's largest producer of consumer and commercial pyrotechnics, and nearly all fireworks sold in the U.S. are imported from China. Hundreds of American fireworks retailers, including Phantom, which is America's largest, have been pressing the administration not to impose a 25% import tax as part of the ongoing trade war.
"It would be pretty devastating," Bill Weimer, vice president of Phantom Fireworks told ABC News of the threatened tariff. "The problem is there's no alternative source for us to get the fireworks. We have to stay with China."
On Tuesday, after returning from Asia and stepping back from an escalating tariff fight, Trump hailed Phantom Fireworks in a tweet to his 61 million followers.
"Thanks to "Phantom Fireworks" and "Fireworks by Grucci" for their generosity in donating the biggest fireworks show Washington D.C. has ever seen," Trump tweeted. "CEO's Bruce Zoldan and Phil Grucci are helping to make this the greatest 4th of July celebration in our Nations history!"
Trump's praise of the companies also appeared to skirt federal ethics guidelines, which prohibit any executive branch employee from using his position to promote a business, product or person.
The White House declined to comment about the potential conflict of interest.
In an interview with ABC News, Grucci said he was providing pro bono services for the event, designing, producing and engineering the fireworks display as a "goodwill gesture."
"It's a gift to the American people," Grucci said.
The family has produced fireworks displays for eight presidential inaugurations and the nation's millennium celebration in 2000.
"To politicize something like this and our involvement is a disappointment to me," Grucci said. "This performance is different. It's bigger and wider and better than anything before. It's something we all can be proud of."
The Interior Department, which is overseeing the display, called Phantom's contribution to the Fourth of July festivities an "extraordinary donation for a phenomenal fireworks display."
House Democrats chided the administration for accepting the gift at a time when some federal agencies were turning away donations for migrants at the border, citing a law that places limits on what agencies can receive without congressional permission.
"It's ironic that President Trump is willing to spend millions of taxpayer dollars and accept donations of fireworks for his partisan Fourth of July celebration while his Administration is turning away donations of diapers and toothpaste for immigrant children separated from their families and held in inhumane detention centers at the border," House Oversight Committee Chairman Elijah Cummings told ABC News.
Some ethics watchdogs also said that the fireworks donation could be construed as an in-kind political contribution to Trump's reelection campaign. Even though the event has been billed as an official White House function, critics say it has the appearance of a patriotic photo op with political overtones.
"Such large, in-kind donations to an event touted by President Trump could be used to help curry favor with him and the administration," said Sheila Krumholz, executive director of the Center for Responsive Politics. "His tweets confirm that they are greatly appreciated and, because they're not going directly to his campaign or another political committee, they can bypass contribution limits."
ABC News' Katherine Faulders contributed to this report.