From PEOPLE Magazine Click to enlarge
On her first day as America's "Second Lady," Jill Biden had bunk beds moved into the Vice Presidential residence at the U.S. Naval Observatory so that her grandchildren could spend Inauguration night. On the 16th day, she rolled out homemade dough in the Navy stewards' basement kitchen for son Hunter's traditional birthday chicken potpie. And in between, on her eighth day, Biden stood at the front of a drab beige classroom at Northern Virginia Community College and introduced herself to her 48 new pupils: "Call me Dr. B."

For Doctor Jill Biden, 57, diving back into teaching at a new school after just a five-week break to celebrate the holidays and move to Washington, D.C., was born of her passion for the profession—and self-preservation. "I want to do what I love," the 28-year teaching veteran told PEOPLE over coffee and bite-size brownies in her living room. "I knew if I let any time lapse, I would be sucked into Joe's life."

While a working Second Lady is not unique (during her husband's VP tenure, Lynne Cheney was a salaried think-tank scholar), it's still something of a novelty. Biden, an English teacher with a school cubicle for an office, brings her work home, where she occasionally corrects her husband's grammar—"Thankfully, in private," he jokes—and spends hours on her students' essays. "She makes the time to listen to her students, to find out if they are learning," Joe Biden says admiringly. Dr. B has another influential cheerleader in First Lady Michelle Obama. "I am so glad Jill is teaching," says Obama, a career woman herself not long ago. "It's so important to keep something for yourself."

Biden finds it hard to keep just about anything for herself these days. The five-mile-a-day runner is now accompanied by jogging Secret Service agents, and she can't stop at Bloomingdale's to buy a comfy pair of loafers without The Washington Post writing about it. She's also grown weary of blogosphere snickering over her preference for being called "Dr." "Ya know, I worked hard for that degree," she says of the Doctorate in Education she completed in 2007. "I earned that title."

The oldest daughter of a banker dad and homemaker mom, Biden holds her other titles—wife and mother—just as dear. She and Joe, now 66, met on a blind date in 1975—a time when the freshman senator from Delaware was still devastated by a Christmastime car accident not quite three years earlier that killed his first wife and baby daughter and seriously injured his two toddler sons, Beau, now 40, and Hunter, 39. (The family still goes to Mass each year on Dec. 18 in honor of the two lives lost.) The couple married two years later and daughter Ashley arrived in 1981. Ashley, now 27 and a social worker, remembers her mom teaching full-time—first high school, then at Delaware Tech—and taking classes at night, all with a sense of humor. "She taught our family the importance of laughter in good and bad times," says Ashley. For his part, the Vice President says his favorite thing about his wife is "her absolute unpredictability." (As if to prove his point, she snuck into his White House office on Feb. 13 to scrawl her Valentine message—"I LOVE YOU, XOXOXOXO!"—across his windows in washable red paint.)

Friendship is also vital to Biden's sense of well being, and she quickly bonded with Obama, whose 7-year-old daughter Sasha is in the same Sidwell Friends School class and basketball team as Biden's granddaughter Maizy, 8. "When you're older, friends don't happen that easily," Biden says. "But Michelle and I clicked right away. We talk about girl things—like, 'Where did you get those shoes?'—as well as issues." They share a deep concern for military families and are teaming up to address a variety of the emotional and financial stresses such families suffer during long deployments.

Coupled with teaching two 2 1/2-hour classes twice weekly and attending to official duties such as hosting receptions for lawmakers and foreign dignitaries, Biden faces a hectic schedule. Yet she wouldn't have it any other way. "I can have my own job, my own life, but also work on issues," she says. "I can have it all, really."