General David Petraeus had just assumed his new role as US Central Command chief in 2009 when he began introducing his staff to a young Harvard University researcher who was writing his biography. The woman, Paula Broadwell, then 37, had never written a book and had almost no journalistic experience. But that wasn’t the only thing about her that made the general’s aides nervous.
Petraeus — already the most acclaimed US military commander in recent decades — had until then been extraordinarily careful in managing his public image, allowing limited access to a handful of journalists, former aides say. Yet, when it came to Broadwell, he seemed eager to throw his own rulebook out the window.
Over the next two years, the two would spend hundreds of hours together in interviews, in Petraeus’s headquarters in Tampa, Fla., and, later, in Kabul, where he was sent as commander of US troops in Afghanistan. They ran together and occasionally traveled together in Petraeus’s military airplane.
The general appeared to have developed a special bond with his enthusiastic but untested biographer, aides say, and Broadwell appeared willing to take full advantage of her special access.
‘‘I found her relationship with him to be disconcerting,’’ said a former aide to the Petraeus, one of several who insisted on anonymity in order to speak candidly about his former boss. ‘‘Those who worked for him never tried to leverage our relationship with him. It seemed to a lot of us that she didn’t have that filter.’’
The full extent of the bond was exposed Friday when Petraeus, 60, abruptly resigned as CIA director, acknowledging in a statement that he had been unfaithful to his wife of nearly 40 years.
Telephone and e-mail requests for interviews with Broadwell were not returned.
For Broadwell, who is also married, the startling turn of events has reportedly been painful as well. After writing a best-selling and highly laudatory book about Petraeus, she appears to have initiated the series of events that led to his public humiliation. Investigators say threatening e-mails from Broadwell to another woman led to the discovery of the affair between the biographer and her subject. It is an outcome made more poignant because she has been — and remains — zealous in her devotion to the general, friends and colleagues say.
‘‘She was relentlessly pro-Petraeus,’’ said a longtime Afghan policy expert who met Broadwell in Kabul. ‘‘There was no room for a conversation of shortcomings of the Petraeus theology. She wasn’t a reporter. She struck me as an acolyte.’’
Despite the obvious closeness between the two, former aides said, that they could be having an affair was unthinkable, mainly because Petraeus came across as a consummate gentleman and family man.
According to her own account, Broadwell met Petraeus in 2006, when she was a graduate student at Harvard’s Kennedy School of Government. Petraeus had gone to Harvard to talk about his experiences as commander of the 101st Airborne Division during the 2003 invasion of Iraq and about a new counterinsurgency manual he was developing. After the presentation, Broadwell — an Army reservist and, like Petraeus, a West Point graduate — was invited to attend a dinner with the general and a few other students.
‘‘I introduced myself to then-Lieutenant General Petraeus and told him about my research interests,’’ she would write in her book, ‘‘All In: The Education of General David Petraeus.’’
In 2008, while pursuing a doctorate, Broadwell decided to write a case study of Petraeus’s leadership style. After several e-mail exchanges, Petraeus, an avid runner, invited her to discuss her project during a run along Potomac River in Washington. The two discovered a common bond: Broadwell, a high school track star who won awards for fitness at West Point, earned the general’s admiration by keeping up with his grueling, six-minute-mile pace.
Soon after, Broadwell decided to turn her dissertation into a book. With the blessing of Petraeus, she made the first of about a half-dozen extended trips to Afghanistan to spend time with him and interview members of his senior staff and field commanders.
Aides were stunned by the close access that Broadwell was granted — and that she occasionally flaunted. At the same time, some were unimpressed by her reporting style and thin journalistic résumé.
‘‘Her credentials didn’t add up,’’ said a former Petraeus staff member who was interviewed a number of times by Broadwell. ‘‘I was underwhelmed’’
Broadwell impressed others who met her because of her hard work, intelligence, and seemingly inexhaustible energy, traits that often are associated with Petraeus. Journalists who befriended her were struck by her idealism and passion for favorite causes, including a wounded-warrior project that she has promoted, sometimes with Petraeus’s help.
‘‘Paula is an impressive woman — high energy, smart, a classic overachiever,’’ said Thomas E. Ricks, who came to know Broadwell while researching his new book, ‘‘The Generals,’’ which is in part about Petraeus.
Other friends and acquaintances also described her as driven and high-achieving. Broadwell, a North Dakota native, was valedictorian and prom queen of her high school graduating class and a member of the state’s all-star basketball team. She graduated from West Point with a degree in political geography and systems engineering and finished first in her class in fitness.
After college, she served for more than a decade in the Army, attaining the rank of major before leaving the military to attend Harvard.
Broadwell, who turned 40 on Friday, lives in Charlotte, N.C., with her husband and her two sons.
In the acknowledgments of her book, Broadwell credited her successes in part to her husband, an ‘‘amazing and supportive partner,’’ who ‘‘played Mr. Mom for our two boys while I was in Afghanistan.’’ Then she thanked Petraeus for his cooperation, saying his ‘‘willingness to indulge my endless questions . . . provided me with a once-in-a-lifetime education.’’