Gary Cohn, Donald Trump's former economic advisor, warned that the Beijing-Washington trade war will impose unwanted taxes on Americans.
He told the BBC that he agreed with the US president's move to lower the US corporate tax rate, but said US tariffs on Chinese goods would be equivalent to excise duty.
The US and China have been fighting for months for months.
Mr. Cohn spoke to Karishma Vaswani of the BBC in Singapore.
Both countries have imposed several customs rounds on each other's goods – and Mr Trump has warned that potentially more tariffs may be set in motion.
However, Mr. Cohn has warned that the trade war between the two giants is simply hurting the backseat of many American consumers – which in turn will harm the US economy.
"We are not a producing economy," he said. "So if US citizens can buy products cheaply, they have more money on goods and if they spend goods, they can take the extra money they have and they can save it – and we need a higher savings rate in the US.
"I consider tariffs as a kind of excise tax [and] We do not want to tax our consumers if they raise their disposable income for what we produce, that is, services. "
Mr Cohn said Mr Trump has a clear idea of what he wants to achieve in further trade negotiations with China.
"The president has his style, he has his tactics," said the former adviser.
"People have questioned him all the way … [but he] is advancing trade, protecting US companies, protecting jobs in the US – he knows he has to do that in the end. "
It was never believed that Cohn and Trump were close, but Goldman Sachs, the 57-year-old ex-manager, helped the president push through his comprehensive tax reforms late last year.
Mr. Cohn's withdrawal from the White House was announced in March, which contributed to a series of high-profile departures.