The television network said Joosten had died Saturday from lung cancer.
“Her family was with her,” Nadine Jolson, Joosten’s representative, is quoted as saying. “Funeral arrangements are pending. This is a terrible loss, and she fought as hard as she could.”
Joosten won the Emmy awards for Outstanding Guest Actress in a Comedy in 2005 and 2008 for her role on the show.
Before joining “Desperate Housewives,” Joosten played in “Dharma and Greg,” “My Name is Earl” and “Ally McBeal.”
She also earned accolades for her role as the president’s secretary in the series “The West Wing.”
Joosten began her acting career at the age of 42, after spending many years working as a psychiatric nurse, NBC News said.