Sunny, nearly 4, came along in August 2013.
Bo already had a job as a "helper" to Dale Haney, the head groundskeeper at the White House, which happens to be a national park.
"He leaves every morning and he goes down with Dale ... and he's with all the National Park Service guys. And you'll see him, and he's like walking around with them, and looking at the plants," Mrs. Obama said. "I think he thinks he has a job because he takes it very seriously. So if I go out and see him, he kind of ignores me when he's with his worker crew people."
The dogs have a pretty nice life. "They can sit on my lap, they sit on my chair, they cuddle with me," Mrs. Obama said. "I like to lay on the floor with them and blow in their face. I like to make them run and chase each other. But they're so cute, I just love to just cuddle them and massage them."
Presidential pets are always popular and many presidents kept dogs as companions. President Harry S. Truman famously advised: "If you want a friend in Washington, get a dog."
President George H.W. Bush's English Springer Spaniel, Millie, "wrote" the best-seller "Millie's Book."
President Bill Clinton's chocolate Labrador Retriever, Buddy, helped Clinton weather the scandal over his affair with White House intern Monica Lewinsky.
President George W. Bush's Scottish Terrier, Barney, had an official web page and starred in "Barneycam" videos that were filmed from a camera hung around his neck. Like Mrs. Obama, first lady Laura Bush was involved with the video scripts and the taping schedule.
President Lyndon B. Johnson angered animal lovers by lifting his pet beagle, Him, by the ears in front of news photographers.
Obama promised last year to "clean things up a little bit" before leaving the White House in January because the dogs "have been tearing things up occasionally."
Mrs. Obama said her four-legged family members had been nice overall, but she exposed Sunny's naughtier side.
"You know what she does sometimes? She leaves the kitchen and she'll sneak and she'll go poop on the other end of the White House," the first lady said.