He celebrated with a free, rooftop concert in his native Seattle.
The surprise appearance atop Easy Street Records, in the Lower Queen Anne neighborhood, was part of a previously planned album signing.
"It's a dream come true," Macklemore, aka Ben Haggerty, said immediately after the concert, "It's a very surreal feeling. There are no real words to describe that."
"To go number one in America is not something you anticipate," added producer Ryan Lewis.
Just last week, Macklemore was in the news for his song with Lewis called "Same Love," which supports marriage equality. The accompanying video, which tells the story of a gay couple, sparked a flurry of interest online and as of Tuesday had nearly 3 million views on YouTube.
"This is an issue of civil rights, and human rights, and it is important," said Haggerty, "I've been wanting to do something for a while, and didn't know how to do it."
Lewis says, "He wanted to write it (for a while) It's about making something personal. Overall, the response has been loving."
The Duo begins a national tour this week, which includes a sold out at show at Seattle's WAMU Theater.