Investors brushed aside data showing weak first-quarter economic growth, which was tied to the severe winter that hampered exports and hit investment spending.
The Fed said in a statement it would reduce its monthly bond purchases to $45 billion from $55 billion, as expected. That will keep it on track to end the program as soon as October.
Fed's looked past a dismal reading on first-quarter growth reinforced the view that weather was to blame for the weakness, analysts said.
Nine of the 10 S&P 500 sectors ended in the black, led by the economically-sensitive S&P materials sector, up 0.8 per cent. Exxon Mobil, up 0.9 per cent at $102.41, led gains on the S&P 500.
The Dow Jones industrial average rose 45.47 points, or 0.27 per cent, to 16,580.84, a record high close.
It was the first record close of the year for the Dow.
The S&P 500 gained 5.62 points, or 0.3 per cent, to 1,883.95 and the Nasdaq Composite added 11.013 points, or 0.27 per cent, to 4,114.556.
For the month, the Dow and S&P 500 posted slight gains, while the Nasdaq dropped 2 per cent following weeks of heavy selling in tech and biotech "momentum" stocks. The Dow was up 0.7 per cent in April; the S&P 500 was up 0.6 per cent.
Stocks were near steady for most of the session, then slowly edged to session highs following the Fed announcement.
EBay was among the biggest negative influences on both the S&P 500 and Nasdaq. Its shares fell 5 per cent to $51.83, a day after it forecast lower-than-expected earnings this quarter.
Twitter shares fell 8.6 per cent to $38.97 and hit a record intraday low of $37.25, a day after posting dismal user and usage growth.
Data showed gross domestic product expanded at a 0.1 percent annual rate in the first quarter, the slowest since the fourth quarter of 2012, as exports and inventories weighed, but activity already appears to be bouncing back.
In another report, however, US private employers beat expectations by adding 220,000 workers in April, the most since November, and gains in the prior month were revised up.
After the bell, shares of Yelp Inc, the operator of consumer review website Yelp.com, rose 4 per cent to $60.67 as it reported a 66 per cent rise in quarterly revenue.
About 6.8 billion shares changed hands on US exchanges, above the 6.6 billion April average, according to data from BATS Global Markets.