"We are stepping in where federal courts have discontinued issuing marriage licenses," Bowser said.
The Let Our Vows Endure Emergency Act of 2019, or LOVE Act, grants Bowser the authority to issue the licenses and authorize officiants for 90 days.
"Today once again we call on the president to get the federal government open, we call on all Americans to join us in our fight for D.C. statehood, and last but not least, we congratulate all the couples who are here with us today, all of those who are out in the city," Bowser said.
She was joined by several soon-to-be-wed couples at Friday's bill signing.
Danielle Geanacopoulos stood beside a man she called her "semi-husband," Dan Pollock.
"I say 'semi' because as some of you may know, we held our wedding ceremony December 29 without our marriage license because of the president's shutdown," Geanacopoulos said. "With Mayor Bowser and the city council's hard work, we're delighted to finally be able to make our commitment to each other legal and binding."
The D.C. City Council on Tuesday voted unanimously to approve the measure, drafted by Bowser's office soon after she was sworn into office for her second term.
“Just like the Grinch can’t steal Christmas, the shutdown can’t stop love,” John Falcicchio, Bowser’s chief of staff, said in a statement at the time.
Though some functions of the federally funded D.C. Superior Court remain operational, the Marriage Bureau, which is a part of the D.C. court system, was deemed nonessential and halted its operations when the federal government shut down.
Pollock, who attended Friday's bill signing, took to Twitter on Dec. 27 to blame President Donald Trump for postponing his wedding.
"Thanks to you, the DC marriage bureau is furloughed the week of our wedding!" he wrote.
Sen. Richard Blumenthal, D-Conn., was one of many who responded to Pollock's post on Twitter, wishing them luck and pointing out that he knows them. He included a link to a story in Buzzfeed, which explained that Pollock lives in New York City but used to work for the senator.
"Like rain on your wedding day, maybe shutdowns are good luck," he wrote on Twitter. "Sure hope so, because this beautiful couple really deserves it! Each is a caring, loyal, whip-smart, dedicated, magnificent person -- as I can personally attest. Much happiness!"