In between, Obama attended a National Prayer Service at the National Cathedral, sharing a pew with Vice President Joe Biden and his wife, along with former President Bill Clinton and future secretary of state Hillary Clinton.
During the afternoon, Obama hosted an open house of his new home, telling visitors to roam around, just don't break anything.
Even during the balls on Tuesday night, Obama was plotting his first steps today.
"Starting tomorrow, we'll be making a series of announcements both on domestic and foreign policy that I think will be critical for us to act swiftly on," he told "Good Morning America's" Robin Roberts at the Neighborhood Ball. "We're not going to be able to delay."
As Obama charged through the long and emotional day Tuesday -- from attending a private church service in the morning to delivering his inaugural address to dancing well past midnight -- much of his staff got right to work.
Just hours after Obama took the oath of office, Emanuel sent a memorandum to federal agencies and departments, calling for them to halt pending regulations until the Obama administration reviewed them.
The new president's biggest priority will be reviving the faltering economy, and that includes hammering out with Congress the details of a massive $825 billion bailout.
"They want to have a complete overhaul of this financial-rescue package within days," said ABC News' chief Washington correspondent George Stephanopoulos.
Obama will meet with senior economic advisers in the afternoon to discuss the stimulus package as well as the $350 billion in Troubled Asset Relief Funds that Congress approved at his request last week to stabilize the financial markets.
To underline the urgency of devising an economic plan, the stock market took its biggest ever inauguration day plunge Tuesday, with the Dow Jones industrial average dropping 330 points, and today's headlines warned of a worsening bank crisis.
Iraq is also high on the Day One agenda. In the late afternoon, Obama will meet with his top generals, including Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen, National Security Adviser Gen. Jim Jones (Ret.) and Gen. David Petraeus, who heads the U.S. Central Command. Joining the meeting via teleconference from Iraq will be U.S. Ambassador to Iraq Ryan Crocker and Gen. Ray Odierno, the top ranking U.S. general in Iraq.
It's not clear whether Clinton will be confirmed as secretary of state in time to sit in on the session.
Obama will be briefed on the status of military operations, and he will command the team to begin making plans to withdraw all U.S. combat troops from Iraq within 16 months.