"Obamacare" plans are private plans; Medicaid is government-run coverage
The most important difference between Medicaid and Obamacare is that Obamacare health plans are offered by private health insurance companies while Medicaid is a government program.
Medicaid, the government health insurance program for low-income United States residents, is a social welfare program like SNAP food stamps or Temporary Assistance to Needy Families.
The term Obamacare is typically used to describe private health insurance purchased through the Affordable Care Act’s health insurance exchanges.
Obamacare health insurance plans are offered by health insurance companies such as Blue Cross, Kaiser Permanente, Molina, Aetna, Humana, Wellpoint, and others. Obamacare health plans are not run by the government.
It's worth noting, however, that more than three-quarters of Medicaid enrollees nationwide are on Medicaid managed care plans, which means that their insurance is administered by private insurers that also sell commercial insurance to individuals and businesses. Those plans operate via a contract with the state government to provide Medicaid benefits.