President Barack Obama has nominated former UnitedHealth Group Inc.'s Optum unit executive vice President Andy Slavitt to be the administrator of the Centers for Medicare & Medicaid Services (CMS).

CMS is charged of overseeing the health programs for the country's poor, disabled and elderly on top of its responsibility for many of the efforts associated with the health care overhaul of the Obama administration. It provides coverage for over 50 million disabled and elderly individuals in the U.S.

The nomination is subject to the approval of the U.S. senate.

Slavitt, who started working for the government in 2014, has been acting as the administrator of the CMS since February this year.

In 2013, he helped fix the fix the federal health insurance website, healthcare.gov, which was crucial for the roll out of the administration's Affordable Care Act. At the time, Slavitt was with the UnitedHealth, which contributed to the site.

Slavitt testified in hearings as those opposed to Obamacare attacked the failures of the website. UnitedHealth's Optum division, however, managed to fix the website well enough to deflect many criticisms and attract the White House's attention leading to the Obama administration eventually naming Optum as the private manager of the website tasked to work out its kinks.

Slavitt's effort was seen as good enough that he later earned a post as principal deputy administrator of CMS in July 2014. After seven months, he was named the acting administrator of the agency.

Slavitt's nomination was welcomed by Sen. Amy Klobuchar, D-Minn., who said that Slavitt has a track record of an innovative and effective leader who gets results adding the Slavitt played an important role in efforts battling health care frauds as well as in reforms in the delivery of health care and improvements in health outcomes.

Klobuchar said that this makes Slavitt the perfect person to lead the agency. Groups that represent doctors and hospital also said that they were pleased by the nomination.

Utah Republican Orrin Hatch, the chairman of the Senate Finance Committee, however, said that Slavitt still has to answer questions about his UnitedHealth work saying that Slavitt's history in the medical services industry is marked by mixed results.

"Mr. Slavitt's conflicted history in the medical services industry has produced mixed results and raised a number of serious concerns," Hatch said. "Slavitt will need to answer a number of tough questions regarding his former employer and their relationship with the agency."