Mr. Obama joined hundreds of people for the annual event held just steps from the White House. First lady Michelle Obama, daughters Malia and Sasha, and Mrs. Obama's mother, Marian Robinson, also attended the event on a chilly night in the nation's capital.
The First Daughters came under criticism over the weekend for their appearance and apparent disinterest in their presidential father's activities, but their smiles were in bright evidence Thursday evening.
Obama said the national tree is a "symbol of hope and holiday spirit." He urged Americans to remember members of the US military serving overseas, as well as their families.
"As we hold our loved ones tight, let's remember the military families whose loved ones are far from home," Obama said. "They are our heroes."
This year's ceremony marks the 92nd annual lighting of the Christmas tree near the White House. The National Park Service says the tradition was started by President Calvin Coolidge in 1923.