In a brief LinkedIn post Thursday, the Bridgewater Associates head said a soft currency is exactly what the U.S. doesn't need right now.
Dalio described a weak dollar as "a hidden tax on people who are holding dollar-denominated assets and a benefit to those who have dollar-denominated liabilities."
In other words, while the greenback decline might make U.S. debt look cheaper on a relative basis, it also makes it less attractive to hold for foreign governments who are counted on to buy bonds and help keep the government running.
More specifically, Dalio said a weakened dollar would: reduce Americans' buying buyer around the world; devalue debt and hurt foreign holders; provide paper wealth to holders of assets like stocks; increase inflation; and boost domestic activity.
"None of this is what the U.S. economy needs now," he wrote. "While it's described as a desirable and intended thing, it might not be a choice."
He further warned that dollar holdings are high right now "so rebalancings should be expected over time." That could be perilous at a point where "U.S. dollar bonds look unattractive and trade tensions with dollar creditors intensify."
Mnuchin made comments advocating for a weak dollar on Wednesday at the World Economic Forum in Davos. On Thursday he tried to elaborate on his position, noting that the administration still backs a strong dollar in the long term.
However, the dollar fell against its global competitors both days, reaching a 12-month low Thursday, and is down more than 11 percent over the past 12 months. President Donald Trump himself has said that a weak dollar is preferable for the U.S. economy at this point.
Dalio, who runs the largest hedge fund in the world with $150 billion in assets, was not alone in his criticisms. Banking analyst Dick Bove of the Vertical Group also said Mnuchin's comments threaten to unravel the economic recovery.
Interestingly, Moody's Investors Service said the dollar's longer trajectory could be higher, despite the dive this week.
"We expect to see dollar volatility as U.S. policy discussions progress, but overall for 2018 we expect the U.S .dollar to strengthen slightly given the continued tightening of US monetary policy," said Elena Duggar, associate managing director at Moody's.
WATCH: Mnuchin not worried about the dollar.