In an interview with CNN's Ana Cabrera on Sunday, Ron Reagan was quizzed on his opinion of Mr Trump’s children’s involvement in the administration and his campaign.
In response the commentator said that he believed the family are “entitled to go and campaign” for their father but then scathing labelled them “grifters”.
“I don't mean to be blunt but we've got a bunch of grifters there in the White House,” he said.
“They are treating this as a grift. They are mixing business with pleasure. They are mixing business with statecraft.”
The Trump campaign and the White House have not yet responded to The Independent’s request for comment on Ron Reagan's remarks.
Mr Trump and his family have been accused on a number of occasions of profiting unlawfully from his presidency and violating ethics regulations for profit.
Earlier this year, Mr Trump and Ivanka Trump faced backlash for publicly posting photos posing with Goya Foods products and were once again met with questions about potential ethical violations and conflicts of interest.
At the time, White House spokeswoman Carolina Hurley defended Ms Trump in a statement to CNN, where she said the president’s daughter showed personal support for the product.
The president is also facing several lawsuits that accuse him of illegally profiting off the presidency through his business interests.
Mr Reagan, a liberal commentator who has been an outspoken critic of Mr Trump in the past, also went on to criticise Ms Trump and her husband Jared Kushner’s role as senior advisers to the president.
“Jared Kushner and Ivanka Trump have no qualifications whatsoever to be in the position that they are in. Zero, zip and they are using it to make money basically,” he said.
Ms Trump previously worked as an executive vice president of the Trump organisation.
Mr Kushner, the president’s son in law, is an investor, real-estate developer, and newspaper publisher.
Dealing a final blow, Mr Reagan went on to say that he believed his father would be “horrified by the Republican party right now” and that the current White House would “shock him”.
“It's gonna be a dark road or a more progressive road. I don't think going back to the days of Ronald Reagan is the answer for the Republican party but they don't have much else and Donald Trump has done a tremendous amount of damage to this party,” he said.
“The spinelessness in the face of this pathological entity in the White House right now would shock him. I know his character and I know what would horrify him and I know this administration would.”
The president is still trailing Joe Biden in the polls of key swing states that could decide the election on 3 November.