"Of course," Obama said when a group of reporters asked if he felt nostalgic.
Walking past a group of reporters Obama was asked "how's it going?"
When asked for any last words to the American people, he said "thank you."
Obama was seen through the window leaving some papers on the Oval Office desk before he came out.
Thereafter, he was followed down to colonnade toward the White House by Vice President Joe Biden and wife Jill Biden, as well as other aides.
News agency Associated Press reported that all of the living American presidents were scheduled to attend the swearing in ceremony, except for 92-year-old George H.W. Bush, who was hospitalized this week with pneumonia. His wife, Barbara, was also admitted to the hospital after falling ill. Trump tweeted his well-wishes to the Bushes, saying he was "looking forward to a speedy recovery."
Obama, who will continue to live in Washington, began his day with a final visit to the Oval Office and goodbye tweets echoing a farewell letter he had penned to the American people.
"I won't stop," he tweeted. "I'll be right there with you as a citizen, inspired by your voices of truth and justice, good humor, and love."
(with inputs from PTI and Associated Press)