Inventory investment probably added to output after making no contribution in the first quarter.
"These numbers are very, very sustainable", Mr. Trump said.
Still, Mr Lynch said he sees the pace of United States growth easing to an annualised rate of 2.9 per cent through the second half of 2018, from 3.1 per cent in the six months through June.
A measure of domestic demand surged at a 4.3pc rate in the second quarter.
Contrary to Trump's assertions, the economy enjoyed periods of robust growth during the Obama administration. Notably, consumer spending perked up quite a bit, rising at an annualized 4.1% rate in Q2 - the fastest since 2014 - and almost double the gain in the previous quarter.
His large package of tax cuts has boosted growth.
The value of the dollar immediately rose and Treasury yields jumped in response. Stock futures pared gains temporarily, and the market opened lightly higher.
Analysts said that increase was due to stockpiling by Chinese importers before Beijing's retaliatory tariffs on USA goods hit in July, which means trade is likely to fall off in the third quarter, dragging down the growth rate.
It remains possible then, that reality will prove Trump's ebullient optimism about the future of American economic growth right. With a healthy tailwind coloring expectations, the next round of numbers will be closely read for clues about how the year's second half will compare, starting with next week's main event for economic releases: payrolls for July (scheduled for Friday, August 3).
The numbers were driven by consumers who began spending the tax cuts Trump signed into law past year and exporters who have been rushing to get their products delivered ahead of retaliatory tariffs. "Look at the average for the first two quarters, it's now 3.2 percent".
"Real consumer spending rebounded, as expected, at a 4.0 percent pace, with gains in durable and nondurable goods as well as services".
"Ironically, the threat of a trade war appears to have bolstered activity in the second quarter", said Michelle Girard, chief economist at NatWest Market in Stamford, Connecticut. Exports added more than a percentage point to growth, something that hasn't happened in years and is unlikely to repeat.
The rush to offload soybeans, however, depleted farm inventories.
Exports surged last quarter amid fears of rising trade tensions and retaliatory tariffs being imposed by top U.S. trading partners. The change in the seasonals has clearly changed the distribution of growth over the course of the year. A further moderation is likely as the trade wars cast a pall on the business spending outlook. If anything, trade could curtail growth later this year if foreign companies buy less from the United States.
Investment in homebuilding fell for a second straight quarter in part as an acute shortage of houses available for sale reduced brokers' commissions.