She made her debut at the Met in 1962 as La Cieca in Gioconda. Her roles included Geneviève, Mistress Quickly, Ulrica, Maddalena, Azucena, Adalgisa, Erda, Amneris, Auntie (Peter Grimes) and La Frugola, the Princess and Zita (Il trittico). During her career, she sang with, among others, Birgit Nilsson, Carlo Bergonzi, Renata Tebaldi and Zinka Milanov. Under Eugene Ormandy she recorded Mahler's Das Lied von der Erde for Columbia Masterworks, and she opened the Saratoga Performing Arts Center in August 1966, again with Ormandy. With Leonard Bernstein, she was one of the many soloists in his recording of Mahler's Eighth Symphony.
Chookasian retired from the stage in the 1980s and now teaches at the Yale School of Music.