In 1944, she and her sister Ann founded a production company, Radio House, which prepared singing commercials and transcribed programs.

One of their ideas was produced by the Mutual Broadcasting System in 1945; it was Leave It to the Girls, which had a panel of one man asking women celebrities questions that had been sent in by viewers.

[6] Based on her strong criticism of Spivak's self-promoting program, Rountree created a new radio show, which she called The American Mercury Presents: Meet the Press, debuting on June 24, 1945.

Contrary to the claims of others concerning the program's creator, Rountree developed the idea on her own, and Spivak joined as co-producer and business partner in the enterprise after the show had already debuted.

[8] The foundation published the Leadership Action Alert political newsletter which was mailed on a regular basis to its thousands of members across the country.

It also served as the umbrella foundation for special projects, such as the National Center for Pan-American Studies (NCPAS), a group chaired by Joseph Quinn, which created a political youth leadership exchange program between students in Latin America and the United States.

"I think of Martha as one of the most creative women I’ve ever known,” opined Liz Carpenter, the former White House staff director and press secretary of Lady Bird Johnson.

“She won a wide audience by initiating a thoughtful debate of issues on the air before it became commonplace.”[9] Mrs. William Randolph Hearst described Rountree as “a diesel engine under a lace handkerchief.”[9]