She attended Eleanor Roosevelt High School in Greenbelt, Maryland and graduated class of 1991. She earned a BA in journalism summa cum laude from the University of Missouri School of Journalism. From 1997 to 2004, she worked in the ABC News Political Unit, where she covered presidential politics and public policy issues, and served as producer in the first year of "This Week with George Stephanopoulos." Lemmon graduated with an MBA from Harvard Business School (HBS), where she received the 2006 Dean's Award for her work on women's entrepreneurship. From 2006 to 2010, she worked in the executive office and in emerging markets at the global investment firm PIMCO. In 2010, she was featured on the cover of the HBS alumni magazine for her work on entrepreneurs in conflict and post-conflict zones. Lemmon is also a former Fulbright scholar and Robert Bosch Foundation fellow.