Medicaid and CHIP sign-ups have exceeded 7 million since ObamaCare's new coverage options opened for enrollment last October, the government reported Friday.
The Department of Health and Human Services (HHS) announced that 7.2 million people have gained health insurance through Medicaid or the Children's Health Insurance Program (CHIP), both designed to serve families with lower incomes.
"Medicaid expansion continues to help an unprecedented number of Americans access health coverage for the very first time," wrote Centers for Medicare and Medicaid Services Deputy Administrator Cindy Mann in a blog post.
"The Affordable Care Act has helped families all over the country find the peace of mind that comes with coverage, but it could be doing even more."
The Obama administration and its allies are pressuring GOP governors to expand Medicaid despite political opposition from the right.
Republicans see the policy, in which states pay no more than 10 percent of the expansion costs, as a fiscal no-go.
The HHS says it does not count exactly how many enrollees under ObamaCare were previously uninsured, though the total uninsured rate has fallen steeply in the last six months.
Medicaid and CHIP enrollment takes place year-round in contrast with the healthcare law's private insurance exchanges.