Miller describes herself as "not really a political person," yet she plays a crucial role in the department. She's responsible for ensuring that Treasury has enough money to pay its bills—not to mention overseeing financial regulations, capital markets, and financial institutions. Professionally, this is a huge change for the 57-year-old who spent 26 years at T. Rowe Price, where she climbed the ladder to become director of the fixed-income division. During the global financial crisis, Miller came to Washington several times to talk about the state of the markets. "It was a critical time that was really interesting to me—to see how the government responded with so many programs," she says. In 2009, the White House tapped her for a role at Treasury. She's been proud of the recovery during her tenure—from the government's ability to repay taxpayers by winding down the Troubled Asset Relief Program to keeping the debt-management operations stable. Next on her To Do list? Making sure that debt-ceiling negotiations run smoothly. "We are very fortunate that the world trusts U.S. Treasury securities, and I want to make sure that that continues," Miller says. She also wants to finish the work on implementing Dodd-Frank and think more about the future of housing finance, with the government playing less of a role. Longer term, she wants to tackle retirement security.