DelBene, who starts his new job on Wednesday, will replace Jeffrey Zients, a long-time aide to President Barack Obama who starts a new job as top economic adviser at the White House in the new year.

As head of Microsoft's most profitable division, DelBene was in charge of providing complex software and services, including Word, Excel, PowerPoint and the Microsoft Exchange e-mail system.

Under DelBene's leadership, Microsoft moved toward making the Office suite of applications available online, a departure for the company.

DelBene, husband of U.S. Representative Suzan DelBene of Washington, is volunteering, a White House official said. He will be compensated for his work, but will return his entire salary, which was not released, to the Treasury.

Zients was brought in two months ago to take charge of the contractors working on HealthCare.gov, the broken website at the heart of the signature health reforms known as Obamacare.

The website could not handle traffic when it launched on October 1, slowing enrollments and creating a political embarrassment for Obama, who had promised a smooth roll-out for his signature health reforms. While now functioning more smoothly, it continues to have problems.

The disaster also alarmed Democrats in Congress facing re-election in November 2014.

Health and Human Services Secretary Kathleen Sebelius credited several Democratic senators, including Jeanne Shaheen of New Hampshire, Mary Landrieu of Louisiana, and Chris Coons of Delaware, with the idea of keeping a point person in place for the website.

DelBene will lead HealthCare.gov through the first half of the year, making sure it performs well through the close of the 2014 enrollment period on March 31, Sebelius said in a blog post.

His appointment was lauded by Microsoft founder Bill Gates and Chief Executive Steve Ballmer.

"Kurt is a talented and capable executive, with a track record of successfully managing complex large-scale technology projects," Gates said in a statement provided by Health and Human Services.

Andy Geisse, the chief executive of AT&T Business Solutions, called DelBene a "top-flight" executive and strong leader.

"I've had the pleasure of working closely with Kurt on several critical projects, and he definitely has the right business acumen and technology background for the job," Geisse said in a statement provided by the government.

The Microsoft veteran started work at the company in 1992. His last official day on the job was Monday, although his retirement was announced in July.

He previously worked as an associate at consultant McKinsey & Co., and also worked on the technical staff at mobile communications pioneer Bell Laboratories.