Nasar was born to a German mother and an Uzbek father; CIA agent Ruzi Nazar (Nasar). Her family immigrated to the United States in 1951, then moved to Ankara, Turkey in 1960. She graduated from Antioch College in 1970, and earned a masters' degree in economics at New York University in 1976. For four years, she did research with Nobel Laureate Wassily Leontief. She is currently the Knight Chair in Business Journalism at Columbia University. Her husband is the noted economist Darryl McLeod. She has three children and lives in Tarrytown, New York.

In the August 28, 2006 The New Yorker, Nasar's article "Manifold Destiny" contained the only interview with Grigori Perelman, who solved the Poincaré conjecture, but rejected the 2006 Fields Medal, and examined Fields Medalist S.T. Yau's response to Perelman's proof. Yau threatened to file a lawsuit, but never followed through.