A heavy security presence encircled the historic Hay-Adam hotel near the White House, where the Obamas will stay until January 15, as police set up cement barriers and kept onlookers at a city block's distance.
"He waved! That's cool! Awesome!" said Keith Slade, 43, who was having a drink at a nearby bar when he caught a glimpse of Obama passing by in the motorcade.
Before Obama departed Chicago, he told reporters: "Well guys, I'm looking forward to seeing you guys in Washington... I gotta say I choked up a little bit leaving my house today."
He said a friend of his eldest daughter, Malia, had brought by "an album of the two of them together. They had been friends since pre-school and I just looked through the pages and the house was empty and it was a little tough, it got me," he admitted.
Obama left Chicago aboard a Boeing 757 plane piloted by Colonel Scott Turner, who will be his Air Force One pilot, and arrived at Andrews Air Force base at 7:00 pm (0000 GMT) before being driven to downtown Washington.
His wife, Michelle, and daughters arrived on Saturday. The girls, Malia, 10, and Sasha, 7, are to start school at Sidwell Friends on Monday.
Louisa Dietsch, 53, came out with her husband and their two daughters to watch the arrival of the man who on January 20 will be inaugurated the 44th US president and the first African-American to ever hold the post.
"We are so excited about the change in this country," she said. "It's 'Obama world' at our house. Hard to believe. We cry so much."
Her daughter Nora, 22, a student at Montana State University, said she had a chance to meet Obama at a rally when he was running for president.
"I was lucky to shake his hand," she said, adding that he will face tough challenges with the struggling US economy and the Middle East conflict.
"He must have enormous pressure and it must be the hardest time to come in as president."
Her sister, Cheska, 20, agreed.
"It must be weird looking at the protesters," she said, noting the presence of around two dozen people gathered on the steps of a church near the hotel where the Obamas are staying to protest Israel's military incursion in Gaza.
Some held candles, while others waved Palestinian flags and raised signs that read: "Obama Call for Ceasefire, Please," and "Not in Our Name."
"Where is Barack Obama's voice? Has he been muzzled already?" asked protester Medea Benjamin, speaking over a microphone.
"We didn't expect Bush to speak out but Barack knows better," said Benjamin, of the women-founded anti-war group Code Pink.
"Michelle, if you're in there, there is something called pillow talk. Talk to your husband, tell him to call for a ceasefire," she called out.
Matt Varnham, 23, a tourist from Britain, said he was excited to come out and see Obama arrive, despite the 40 degree Fahrenheit (five Celsius) temperature.
"It's fantastic, it is a momentous occasion," he said, adding that he was eager to see what Obama will do as president.
"His hands are tied because of the system but he'll bring hope, which I think is the most powerful weapon."