She also played Vanessa Bennett on All My Children from 1999 to 2002, "Pamela Pepperidge Capwell Conrad" on Santa Barbara in 1987–1988, 1991 and "Myrna Clegg" on Capitol from 1983 to 1987. In 1993, she filled in for Louise Sorel as "Vivian Alamain" on Days of Our Lives while Sorel was on leave.
She started her career with a small role as a waitress alongside Elvis Presley in the film Clambake in 1967. In 1968, Dusay played a special agent in the TV series Hawaii Five-O in an episode titled "Twenty-Four Carat Kill", as well appearing twice as seductive temptresses on Hogan's Heroes.
Dusay made numerous guest appearances on popular television shows in the late 1960s and 1970s. She played alien "Kara" in "Spock's Brain", the first third-season episode of Star Trek. This episode was written in haste and its outlandish plotline involving the theft of Spock's brain has made it a popular target of derision by Star Trek fans. Leonard Nimoy mentions this particular episode in his book I Am Spock as "Star Trek losing its brain". The book also features a photograph of the actors in character. Despite the perceived shortcomings of "Spock's Brain", Dusay has taken the role in stride and is a popular guest at Star Trek fan conventions, often appearing with personal friend and fellow Star Trek actor Michael Dante.
In late May 2005, Dusay was one of several cast members taken off cotract due to budget cuts. The show later asked her to remain with the show on recurring status.