The first lady tweeted shortly before 11 a.m.: "We just re-opened tours at the White House & I'm about to greet folks right now. Tune in…this is going to be fun! –mo."
The White House posted a video link to the president and first lady greeting guests, and both of the Obamas' dogs were also visible.
“It’s good to have you back,” Obama said to one of the first guests.
Obama asked one young boy where he’s from. The boy said Massachusetts. Obama asked, “Does that make you a Red Sox fan? … That was a good series.”
Michelle pointed out which dog was Bo and which was Sunny. Sunny put paws up on the boy.
The couple engaged in chit-chat with a stream of visitors, discussing everything from military service to passing the bar.
"I've got one question for you — somebody stole your tooth," the president told a 5-year-old boy in his mother's arms.
The tours had been halted since March in the wake of across-the-board budget cuts known as sequestration. The advent of a new spending bill approved by Congress this week allowed the agency to resume the tours “on a limited schedule while still meeting operational requirements,” said Secret Service spokesman Robert Novy.
David Nakamura contributed to this report.