Just one month after assuming her current role, Monaco was briefing the president on the twin bombings that struck the marathon in her hometown of Boston, where she also went to college at Harvard. Monaco, 45, is no stranger to stressful jobs: She was assistant attorney general for national security since 2011 after moving up the ranks at the Justice Department. The University of Chicago Law School graduate was also FBI Director Robert Mueller's counsel and chief of staff. Monaco joined the bureau on detail from the U.S. Attorney's Office for the District of Columbia. Monaco was federal prosecutor for six years until 2007, handling cases such as the prosecution of Enron executives, and served as Attorney General Janet Reno's counsel before that. Center for a New American Security Senior Fellow Phillip Carter, who once led detainee policy at the Pentagon and worked with Monaco when she was at Justice, says she "has the persona of a federal prosecutor"—a tough woman with "no compunction at all about pursuing tougher options in the counterterrorism world." Philip Mudd, who knew Monaco from their FBI days, says her background in law enforcement is quite different from that of her predecessor, John Brennan, who came from intelligence. "The number of people who have senior-executive experience at multiple agencies [like Monaco] is relatively rare," he says.