The regional Democrat whose district includes parts of the Augusta area, parted ways with other Georgia congressmen on a largely symbolic vote to repeal the law.
Barrow, who'd faced backlash in his party for his votes last year, made a U-turn.
The law doesn't solve "the most pressing health care issues this country faces," he said after the vote, but he also insisted that repeal's not the answer.
"We need to keep the parts that prohibit folks from getting denied coverage based on preexisting conditions, and extend health coverage to kids just out of college," he said.
"There are a lot of good things in the bill," he said Saturday at a meeting with constituents. "I don't believe in voting against the parts that are good. ... We need to amend it, not end it."
Charles Bullock, a University of Georgia political science professor, noted that the vote will have little practical effect.
It likely would stall in the Democrat-run Senate, and - even if it didn't - be vetoed by President Barack Obama, Bullock said.
Still, Barrow's vote is politically risky, the professor said.
"Next time," he said, "opponents can say he flip-flopped."
Bullock said Barrow may be trying to mollify Democrats - especially blacks - miffed by his votes last year.
There is widespread speculation that Barrow may end up with a district with more Democrats and blacks after this year's redistricting.
Republicans who will dominate that process want to protect the seat narrowly won Nov. 2 by Austin Scott, of Tifton.
One way would be to shift areas heavily populated by blacks - who vote overwhelmingly Democratic - from Scott's district to Barrow's.
Barrow won the Democratic primary there last year with 58 percent of the vote.
"But if he were to get a more viable challenger in 2012, Bullock said, "and voted for repeal, he might have a harder time."
There's a potential downside, Bullock added.
"In trying to appease voters in the primary election, he may alienate general election voters," he said.