In 2000 she was a student attorney for the American University Community and Economic Development Law Clinic and later a legal intern for District of Columbia Superior Court Judge Nan R. Shuker.

In 2001 she was an equal justice foundation fellow for C-CAPE in Beaufort, North Carolina.

[2] On September 7, 2017, President Donald Trump nominated Jennings to serve as a United States District Judge of the United States District Court for the Western District of Kentucky, to the seat vacated by Judge John G. Heyburn II, who assumed senior status on April 1, 2014.

[5] On April 12, 2018, the United States Senate invoked cloture on her nomination by a 94–2 vote.

[8] On April 21, 2022, Jennings temporarily blocked a Kentucky law that would ban abortions after 15 weeks.