Gross domestic product expanded at an annual rate of 2.3 percent in the April-June period, slightly below the 2.5 percent consensus estimate.
The first quarter, marred by severe winter weather and West Coast port strikes, was not as weak as previously estimated. The department said GDP rose 0.6 percent, revised from a 0.2 per cent contraction.
According to the department's first estimate for the second quarter, growth was fueled mainly be an increase in consumer spending, which accounts for about 70 percent of US economic activity.
There was a major turnaround in exports, which had been hit in the first quarter by the West Coast ports slowdown that choked traffic.
Exports of goods and services advanced 5.3 percent in the second quarter after plummeting 6.0 percent in the first.
Imports, which subtract from the GDP calculation, slowed sharply, rising 3.5 percent, about half the prior quarter's increase.