Trump signed the resolution "rejecting White nationalists, White supremacists, the Ku Klux Klan, neo-Nazis, and other hate groups," which was unanimously passed by Congress earlier in the week.
In a statement, Trump said he was "pleased to sign" the measure, adding that "as Americans, we condemn the recent violence in Charlottesville and oppose hatred, bigotry, and racism in all forms."
The overwhelming passage of the text meant that Trump would have likely had any attempted presidential veto overturned.
Lawmakers from Virginia said Congress spoke with "a unified voice" to unequivocally condemn the August unrest, in which a rally by far-right extremists turned violent and a counter-demonstrator was killed when a car driven by a suspected white supremacist plowed into a crowd.
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Trump was widely criticized for suggesting "both sides" shared blame for the violence between white supremacist groups and those opposed to them.
The president's job approval ratings sank to one of the lowest levels of his turbulent seven-month presidency, as he was savaged over his handling of the fallout from Charlottesville.
Trump earlier on Thursday had appeared to revive his much-criticized suggestion of an equivalence between counter-protestors and those who killed Heather Heyer.
"I think especially in light of the advent of Antifa, if you look at what's going on there, you know, you have some pretty bad dudes on the other side also," Trump said in reference to anti-fascist groups.
"Now because of what's happened since then, with Antifa, you look at, you know, really what's happened since Charlottesville -- a lot of people are saying -- in fact a lot of people have actually written, 'gee Trump might have a point.'"
"I said, you got some very bad people on the other side also, which is true."
