(Byline Withheld/AP Images)

Administration officials confirm that Cass Sunstein is returning to Harvard Law School later this month, with thanks from an admiring president who brought Sunstein into the White House for the unglamorous but powerful job of juggling government regulations.

"Cass has shepherded our review of existing rules to get rid of those that cost too much or no longer make sense, an effort that is already on track to save billions of dollars," President Obama will say when the announcement is made later today.

Sunstein's title has been Administrator of the Office of Information and Regulatory Affairs (OIRA) in the Office of Management and Budget (OMB). The role is considered one of the most powerful in Washington given its ability to shape how laws are implemented, essentially writing the rules for how the government operates.

"His emphasis on transparency and on innovative, low-cost regulatory tools contributed to the Administration's Open Government Initiative; to numerous efforts to promote clear, simple disclosure to inform consumers and investors; and to creative reforms to increase public participation in the regulatory process and to promote accountability to the American public," said OMB director Jeffrey Zients.

Still, Sunstein's tenure hasn't been as revered by many liberal public interest and advocacy groups, which have been frustrated that some of Obama's campaign promises have been tied up in red tape at Sunstein's office.

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This post has been updated. ABC News' Devin Dwyer contributed.