Mary Tsingou was born in Milwaukee, Wisconsin, her Greek parents having moved to the United States from Bulgaria.

In the aftermath of the Great Depression, the family left the US to spend several years in Bulgaria.

[2] Tsingou joined the theoretical division of the Los Alamos National Laboratory, where she became one of the first programmers on the MANIAC.

[2] The analysis became known in the computational physics community as the Fermi–Pasta–Ulam–Tsingou problem (FPUT), and Tsingou's contributions have since been recognized.

[2] The paper published by Los Alamos National Lab in 1955 earned recognition for Fermi, Pasta, and Ulam for its novel discoveries, with Tsingou being acknowledged in the footnote.