Kathleen Sebelius is resigning as head of the Department of Health and Human Services, White House officials confirmed to news outlets Thursday.

Sebelius, who helmed HHS during the crafting and passage of the Affordable Care Act, came under fire after the disastrous rollout of the federal health insurance website in October. While critics have continued to say her mismanagement led to the fiasco, ACA enrollment numbers have surged. News of her resignation broke hours after she told a Congressional panel that HealthCare.gov sign-ups have exceeded 7 million.

President Barack Obama stood by Sebelius throughout the tumultuous rollout, and White House Chief of Staff Denis McDonough told The New York Times that Sebelius had not been pressured to step down.

She will be replaced by Sylvia Mathews Burwell, McDonough said. Burwell has worked in the public and private sector — including for the Bill & Melinda Gates Foundation — and will transition to HHS from her position as head of the White House Office of Management and Budget.  

When Sebelius took the HHS job, she stepped down as the governor of Kansas and was replaced by her lieutenant governor, Mark Parkinson. A successful nursing home and assisted living operator himself, Parkinson now is CEO and president of the nation’s largest long-term care provider group, the American Health Care Association/National Center for Assisted Living.