After graduating from Princeton in 1986, Sewell attended Oxford University. It was there where she befriended Susan Rice. Her master’s thesis, on the election of the first black members of the British parliament, was later published as a book titled, Black Tribunes: Race and Representation in British Politics (1993). She graduated from Oxford with a degree in political science in 1988. She attended Harvard Law School for her J.D. degree, which she completed in 1992. She overlapped with and was friends with Barack Obama, who became a lifelong friend and influenced Sewell’s decision to enter politics.

After graduation, Sewell served as a judicial law clerk in Birmingham, Alabama to the Chief Judge U. W. Clemon, In New York, she worked at Davis Polk & Wardell, alongside Kirsten Gillibrand, starting in 1994.

In 1998, Sewell married Theodore Dixie of Huntsville, Alabama. They are divorced.

Sewell returned to Alabama in 2004, due to her father’s health problems. She worked for another law firm, Maynard, Cooper & Gale PC, where she was the first Black woman partner at the firm. She was a public finance lawyer.

In 2007, Sewell was at Brown Chapel A.M.E. Church, where she is a member, in Selma, when then senator Barack Obama spoke during the 2008 United States presidential election. Sewell credits Obama’s speech (in which he asked “[t]he questions that I have today is, what’s called of us in this Joshua generation? What do we do in order to fulfill that legacy, to fulfill the obligations and the debt that we owe to those who allowed us to be here today?”) as being the catalyst for her serving in politics. Weeks after the Obama speech, Kirsten Gillibrand called Sewell, recruiting Sewell to run for office.

Sewell has been endorsed by the Feminist Majority in past elections. In 2011, Sewell signed the Equal Rights Amendment. Two years later, in 2013, Sewell voted in support of reauthorizing the Violence Against Women Act. In 2019, she voted in support of the Paycheck Fairness Act.

Sewell co-sponsored the STOCK Act in 2011 and the DISCLOSE Act in 2012. That same year, she also co-sponsored the SIMPLE Voting Act, to require a minimum of 15 days of nationwide early voting.

Sewell opposed removing armed forces from Afghanistan in 2011.

Sewell was the only candidate to file for the Democratic nomination in 2012, and won the general election over Chamberlain as in 2010.

Sewell supported Obama’s decisions regarding Afghanistan, citing “trust” for his policies. She was part of a bipartisan delegation to accompany Nancy Pelosi on a 2-day trip to Afghanistan in May 2012. While there, they spent time “with American service-members and meeting local officials to discuss security and women’s issues.”

She has a score of “85” out of 100 for her voting on pro-LGBTQ laws from the Human Rights Campaign. She co-sponsored the Student Non-Discrimination Act in 2013 which, if enacted, would have protected LGBT students from anti-gay bullying and discrimination in public schools.

Sewell was again unchallenged by a Republican in the 2016 general election. She easily won a fourth term against a write-in opponent.

In 2018, the Humane Society of the United States gave Sewell a rating of 45% for her pro-animal welfare voting history. She has a 79% rating from the League of Conservation Voters for her pro-environment voting record.

As of 2018, Sewell has a 96% lifetime score from the Alliance of Retired Americans for her pro-retirement voting record.

Terri Sewell is pro-choice. As of 2018, she has as 100% rating for her voting record on pro-choice legislation by NARAL. Sewell opposed the Human Life Protection Act, which went into effect in 2019. She described the bill on Twitter as “both blatantly unconstitutional and a brazen, extremist attack on women’s rights.”

Sewell is a staunch advocate for voting rights. In 2019, she sponsored the Voting Rights Advancement Act, which would update the Voting Rights Act of 1965, by providing increased oversight over voting changes, updating the pre-clearance formula to oversee contemporary discrimination patterns, and expanding the power of the Attorney General to send federal observers to jurisdictions in areas at risk for discrimination during voting. In 2019, she co-sponsored the For the People Act of 2019.

Sewell is a major supporter of historically black colleges and universities (HBCUs). In 2019, she sponsored a bill, which passed, funding HBCUs $70 million for capital improvements and to support their educational work.

In 2019, Sewell voted in support for the Bipartisan Background Checks Act of 2019, requiring background checks on anyone seeking to buy a firearm.

On December 18, 2019, Sewell voted for both articles of impeachment against President Donald J. Trump and was the lone Representative from Alabama in the House to do so.

In January 2020, Sewell endorsed Joe Biden for president.