Wednesday's vote on repealing the health care bill was mostly symbolic.
After passing the Republican-dominated House, the next stop is the US Senate, where Democrats remain in control. Regardless, Mr Obama has promised to veto the repeal if it makes it to his desk.
A more likely scenario is that Republicans will now begin chipping away at the bill, rolling back or refusing to fund provisions they disagree with, like the individual mandate.
But the repeal vote will have pleased many Republican supporters, particularly those in the conservative Tea Party movement who had angrily decried Mr Obama's reforms.
It has also energised Democrats, who vigorously defended the bill they had once been wary of. They argued that the reform package extends health care to millions of Americans who are currently without it.
Overall Americans remain divided over the health care bill. One new poll shows that a majority believe it will damage the US economy, but only 18% want to see the bill repealed in its entirety.
The president's landmark achievement would provide coverage to more than 30 million uninsured people.
The law would also expand a Medicaid programme for the poor and provide tax credits to make premiums more affordable for the middle class.
"Americans deserve the freedom and security of knowing that insurance companies can't deny, cap or drop their coverage when they need it the most, while taking meaningful steps to curb runaway health costs," the president said in a statement on Tuesday.
But Republicans are challenging the overhaul, which is set fully to take effect in 2014, as unconstitutional in federal court.
Sixty votes in the Senate, which only holds 47 Republicans, would probably be needed to overturn the law - if it passes in the House later on Wednesday.
Many in the US are already benefiting from the overhaul, which has allowed for extended coverage for young on their parents' healthcare plan and lower prices for prescription medicine for Medicare recipients.
The US healthcare reform law was approved in March of last year, making it compulsory for Americans to buy medical insurance and illegal for insurance companies to deny coverage to customers with pre-existing conditions.
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