On the federal holiday named for the slain civil rights leader, Obama brought his family to Stuart Hobson Middle School, where he and first lady Michelle Obama helped paint apple characters on pillars in the lunchroom to encourage healthier eating.
Obama said King's legacy is also about service and urged Americans to get out into their communities on Monday - a step he suggested would have special meaning following the shooting rampage in Tucson, Ariz.
"After a painful week where so many of us were focused on the tragedy, it's good for us to remind ourselves of what this country is all about," he told reporters.
Monday also happened to be Michelle Obama's 47th birthday. To mark it, the crowd at the school sang the Stevie Wonder version of "Happy Birthday," which the musician wrote to honor King.
