The figure is a sharp upward revision from the preliminary estimate, which pegged economic growth from April through June at 1.7 percent.
The second quarter's economic performance is also a stride better than the first quarter, which saw growth at 1.1 percent.
The quarter included positive contributions from personal spending, exports, private inventory investment, commercial real estate and residential real estate.
"The acceleration in real GDP in the second quarter primarily reflected upturns in exports and in non-residential fixed investment and a smaller decrease in federal government spending," the Bureau of Economic Analysis said.
The department said second quarter corporate profits rose by $78.3 billion after falling by $26.6 billion in the first quarter.
Dividends in the quarter rose by $273.8 billion after dropping by $103.8 billion in the first three months of the year.