Biden spent nearly 90 minutes moving from table to table, chatting with about 100 invited guests, most of them families of deployed or recently returned Utah Air and Utah Army National Guard members.
In Utah for a Park City political fundraiser with her husband, Biden was promoting the Joining Forces initiative, which she created with First Lady Michelle Obama to call attention to the needs of military families.
Aaron Kramer was not in the Guard when he died at age 22; he was a U.S. Army ranger, as was his twin, Brandon Kramer, who served as the military escort for his brother's body.
Their father, Rick Kramer, said Biden's empathy Tuesday was welcome. When she spotted the gold stars on his collar and his ex-wife's blouse, she gave each a warm hug.
"She thanked us, we thanked her," he said. "Most people don't even know what's going on over there."
Biden reminded the families that she's a "military mom." Her stepson, Beau Biden, is in the Delaware Army National Guard, and served in Iraq from 2008 to 2009.
The Joining Forces initiative, she said, is to encourage all Americans to support military families.
"It's not just the person wearing the uniform. It's the whole family that gives service to our country," she said in brief remarks punctuated by the screams of 13-month-old Ava Herrscher, whose father is deployed with the 130th Engineering Installation Squadron of the Utah Air National Guard.
"That's OK, I have grandchildren!" Biden said, prompting laughs from the crowd.
Biden also noted that the central Utah city of Richfield was one of the winners of the Joining Forces Challenge last spring, chosen for its community-wide support for service members and their families.
Tonia Johnson brought two copies of Biden's children's book and Flat Daddy a cardboard cutout of her husband, Bradley Johnson to the reception. He's serving with the 130th in Afghanistan; his cutout goes everywhere but the swimming pool with the family.
Biden, who teaches English at a community college in Virginia, wrote "Don't Forget, God Bless Our Troops," and Johnson asked her to autograph her children's copies.
"She is just very for military families," she said. "We know that she's on our side."
Laurie Herrscher, who attended the reception with her husband a 41-year veteran of the Utah Air National Guard daughter-in-law and grandchildren, said such events are not about politics.
"It's respect for the office," she said. "And I respect their service."