[2][6] Feinberg spent a number of years on Capitol Hill beginning in 1999, including working for the Senate Veterans Affairs Committee, as the communications director for the House Democratic Caucus, the press secretary at the Democratic Congressional Campaign Committee, and the national press secretary to then-Senate Minority Leader Tom Daschle.

[4][2][9][7] From 2009-10, she served in the Obama administration as special assistant to the president, and senior advisor to White House Chief of Staff Rahm Emanuel.

[4][5][2] In 2017 she founded Feinberg Strategies, LLC, a strategic business and communications consulting practice focused on the tech sector.

[4][5][11] In March 2020, Cuomo appointed her interim President of the New York City Transit Authority after the resignation of Andy Byford.

[14] Due to opposition to splitting the top role between two people, the state Senate did not act on her nomination; as a result, Feinberg left the MTA on July 30, 2021.