"You will hear a few but loud voices talking obsessively, not about our national greatness, but about our national shortcomings," Vance said from the USS Kearsarge.
The speech came during the 250th anniversary of the signing of the Declaration of Independence.
At the same time, a large number of sailing ships from more than 20 countries entered the harbor to take part in the celebrations.
A series of military aircraft - including the US Navy’s display team - flew over the harbor, some leaving behind red, white and blue contrails.
According to JD Vance, the critics "speak with the same anger and zeal as a doomsday preacher, but without the grace or forgiveness that must be found in the Christian faith."
He also urged Americans to “reject the two-dimensional view” of the country’s citizens and “the two-dimensional view of your country.”
The speech was reminiscent of President Donald Trump's the day before, who used even stronger language in an attack on "radicals and extremists" who threaten America's identity, claiming there was "a return of the communist threat to our country."
The speeches illustrate how the celebration comes at a time of deep political division in the United States.
