The 32-year-old was sworn into office on Thursday, after her historic election victory in the 14th Congressional District in Illinois in November. She is the first woman and black person to represent her district, which is overwhelmingly white.
Rep. Barbara Jordan of Texas was previously the youngest black woman to serve in Congress, when she was sworn in at 36 years old in 1973, according to a page from the History, Art & Archives site of the United States House of Representatives. Jordan died in 1996.
Underwood, a registered nurse, celebrated getting sworn in by posting on Twitter Thursday.
“Here we go, #IL14!” she wrote.
On Wednesday, Underwood shared a video of her taking her first constituent call after moving into her office.
“Thanks for calling Brent from Montgomery!” she wrote on Twitter.
The congresswoman previously served as a senior adviser at the U.S. Department of Health and Human Services during former President Barack Obama’s administration. She won the nomination for her party in March, beating out six white male candidates.
Underwood paid homage to Shirley Chisholm, the first black woman in history to serve in Congress, during her acceptance speech on election night in November.
“When Congresswoman Chisholm ran for president in the 1970s, she proclaimed that she was ‘unbought and unbossed,’ and I’ve adopted that declaration as my own unofficial model,” Underwood said at the time, according to a video by ABC7.
“Together on this night, we made history,” she later added.