Day of service honors Martin Luther King Jr.
President Obama and first lady Michelle Obama planned to mark the day by participating in a service project in Washington.
"Martin Luther King, Jr. lived his life for others, dedicating his work to ensuring equal opportunity, freedom, and justice for all," Obama said in a statement. "I encourage every American to observe this holiday in honor of Dr. King's selfless legacy by volunteering in their own communities and by dedicating time each day to bettering the lives of those around us."
A federal holiday to honor King, who was assassinated in 1968, was first observed in 1986. In 1994, Congress also designated it a national day of service.
A video posted on mlkday.gov, the U.S. government website dedicated to the day, quotes King: "He who is greatest among you shall be a servant. That's the new definition of greatness. ... By giving that definition of greatness, it means that everybody can be great, because everybody can serve."
Vice President Joe Biden and numerous Cabinet secretaries and administration officials are also scheduled to participate in service events, the White House said.
King's son, Martin Luther King III, is scheduled to deliver the keynote address at a memorial service at Atlanta's Ebenezer Baptist Church.
The Rev. Al Sharpton's National Action Network said it planned to mark the day with a breakfast in Washington and a public policy forum in New York.
In a statement Sunday, Interior Secretary Ken Salazar noted that a memorial in King's honor is under construction on the National Mall in Washington.
"When completed later this year, the memorial will serve to remind us of Dr. King's hope, sense of justice, and quest for equality," he said.
A march "for jobs and justice" was scheduled to begin at that monument site Monday and end at the Lincoln Memorial, where King delivered his famous "I Have a Dream" speech.