"The more I see Donald Trump moving toward conflict rather than cooperation, the more I worry about him harming his presidency and its effects on most of us," Dalio wrote in a LinkedIn blog post.
"I have to confess a personal bias that is opposite his — i.e., I'm inclined to optimize for the whole through cooperation in order to make the pie bigger, and then cooperatively and competitively divide up the pie."
Dalio cited Trump's decision to pull out of the Paris climate agreement last week as "consistent with his increasingly clear patterns of behavior" to pursue conflict over harmony.
"I believe that we are connected to our whole ecology, our whole world community, and our whole United States, such that it pays to be in symbiotic relationships with them — so, I'm concerned about his path. I am especially concerned about the consequences of his pursuing so much conflict," Dalio wrote.
Bridgewater is the world's largest hedge fund, managing about $160 billion, according to its website.
Dalio doesn't say how Trump's fighting stance affects his market outlook. In his last big blog post on May 12, the hedge fund manager wrote that the near-term market picture looks OK, but that longer term the economic outlook is "scary" because greater social and political conflict could eventually cause a downturn.