In 1967, Kansas native Dusay was a member of the Session, an improvisational comedy group in Los Angeles, formed by Rob Reiner.

In 1968, Dusay played a special agent in the TV series Hawaii Five-O, in an episode titled "Twenty-Four Karat Kill".

In 1969, Dusay played a woman who agrees to testify against a mobster in "The Singapore File", as well as appearing three times as seductive temptresses on Hogan's Heroes.

[6]: 321  In 1982, she appeared as Kate Hanrahan, a madam/con artist, in several episodes of Bret Maverick,[6]: 134-135  in 1982-1983, she portrayed Beverly Tepperman in Square Pegs,[6]: 1007  and in 1979 she was Jennifer in Stop Susan Williams.

The film made a "festival splash"[8] and was praised by Dave Kehr of The New York Times as belonging "to the small but significant tradition of outsider art in American movies - films like Herk Harvey's Carnival of Souls or George A. Romero's Night of the Living Dead - that reflect powerful personalities formed outside any academic or professional tradition.”[9] Dusay was praised for her performance as "Grandmother Elliot" in A Chronicle of Corpses which culminates in a tour de force seven-minute monologue for her character.

[10] She received uniformly good notices and several acting awards for her work in A Chronicle of Corpses the including winning the prestigious Silver Unicorn for Best Actor ("Unicornio de plata a la mejor Interpretación" — the highest acting honor) at The 3rd Annual Estepona Fantastic Film Festival (held in Spain 23–29 September 2002).

[14] Dusay made her soap debut in April 1983, replacing Carolyn Jones as the powerful Washington, DC, matriarch Myrna Clegg on Capitol,[15] which she played through the final episode in March 1987.

As the rival of the kindly Clarissa McCandless (Constance Towers), she had a part in practically every storyline, as well as a steady leading man in veteran film actor Richard Egan.

After a nationwide search for an actress to take over for the enormously popular Beverlee McKinsey as Alexandra Spaulding on Guiding Light, Dusay was cast in the role and began airing in August 1993, remaining on the show until March 1997.

As the mother of Dr. David Hayward (Vincent Irizarry, her co-star from Guiding Light) and Leo DuPres (Josh Duhamel), she also became Palmer Cortlandt's last wife, playing opposite James Mitchell.

Dusay then once again returned to the role of Alexandra on Guiding Light, this time replacing Joan Collins, who left three months into a six-month contract.