[6] While working for Senator Leahy, Howell helped craft the E-FOIA amendments, which expanded electronic access to government records.

[7][10] Howell was involved in national security issues,[11] including the creation of the USA PATRIOT Act,[7][10] which she defended in 2005 in an article for the Pennsylvania Bar Association Quarterly.

[15] In response, Representative Elise Stefanik, a Republican from New York, filed a complaint of judicial misconduct in which she alleged that Howell's remarks were "conduct unbecoming of a federal judge".

Howell's work at Stroz Friedberg included lobbying on behalf of the Recording Industry Association of America,[7][18][19][20] and, briefly, Universal Music Group.

[9][23] On July 14, 2010, Howell was nominated by President Barack Obama to the seat vacated by Judge Paul L. Friedman, who assumed senior status on December 31, 2009.

[25] In 2011, Harold Hodge Jr. stood outside the U.S. Supreme Court wearing a sign that protested the American government's treatment of black and Hispanic people.

In 2018, Howell struck down a regulation of the Federal Election Commission allowing dark money groups, certain nonprofit organizations engaged in political activities, to conceal their donors.

She wrote that the regulation "blatantly undercuts the congressional goal of fully disclosing the sources of money flowing into federal political campaigns, and thereby suppresses the benefits intended to accrue from disclosure.

[29] In that same year, Howell became the supervising judge for the grand jury working for special counsel Robert Mueller's investigation into Russian interference in the 2016 United States elections.

[1] On October 25, 2019, she ruled in favor of the House Judiciary Committee, which had sought grand jury materials from the Mueller investigation, finding their impeachment inquiry into President Donald Trump to be a judicial proceeding.