She served in the Obama administration as Deputy Director of the White House Office of Health Reform.

In December 2018, Lambrew was nominated to serve as Commissioner of the Maine Department of Health and Human Services by Governor-elect Janet Mills.

She has also served as a senior fellow at Center for American Progress,[4] and she cowrote a book, Critical: What We Can Do About the Healthcare Crisis, with former Senate Majority Leader Tom Daschle.

At a December 11, 2008, press conference, President-elect Barack Obama announced that Lambrew would serve as deputy director of a newly created White House Office of Health Care Reform under Tom Daschle, who was also designated to serve as Secretary of Health and Human Services.

[5] Due to Tom Daschle withdrawing from both positions over tax issues, Nancy-Ann Min DeParle was appointed director.