She received her MFA in Painting and Printmaking at Yale School of Art and Architecture. Heffernan has been exhibiting her paintings actively throughout the world since 1988 and is represented by PPOW Gallery in New York City, Catharine Clark Gallery in San Francisco, CA, Mark Moore Gallery in LA, CA and Megumi Ogita Gallery in Tokyo, Japan. In 2010-11 she had solo exhibitions at PPOW Gallery in NYC, Megumi Ogita Gallery in Tokyo, Japan, and Catharine Clark Gallery in SF, CA. In 2009-11 Heffernan was invited to participate in 26 group shows including The 183rd Annual: An Invitational Exhibition of Contemporary American Art” at the National Academy Museum in NYC; “Old School”. At Hauser and Wirth Gallery, London, England and Zwirner and Wirth Gallery in NYC; and “Arcimboldo-Artista Milanese tra Leonardo e Caravaggio,” at Palazzo Reale in Milan, Italy