The president and his wife, wearing aprons and baseball caps, were assisted by their two daughters, Malia, 11, and eight-year-old Sasha at the facility, located just a short ride from the White House.
On the menu were pre-assembled lunches of chicken, potato salad, mixed vegetables and bread, which the American leader handed out while chatting to the men and women filing into the dining room.
Michelle - who celebrated turning 46 with a meal out with her husband on Saturday - took charge of hot beverages, pouring out coffee while her youngest followed her around distributing sweetener sachets.
Even Michelle's mother, Marian Robinson, was enlisted; she offered pastries, while Malia - displaying the down-to-earth confidence of her mum - spent time chatting and shaking hands with people.
In fact the only member of the family missing was beloved pet dog Bo.
The first family took part in the community service project at So Others Might Eat – SOME - to honour the legacy of Martin Luther King.
It was the first in a number of activities Mr Obama attended on Monday, a federal holiday in the States.
He later hosted a discussion with people involved in the civil rights movement and their grandchildren before delivering a speech at a concert in the Kennedy Center.