According to her husband David Rabe, the actress died from leukemia in their Connecticut residence.
It seems that Jill lived with this illness for 20 years. As for her acting career she appeared in An Unmarried Woman in 1978, Ally McBeal.
Clayburgh said in an interview: “There was practically nothing for women to do on the screen in the 1950s and 1960s. I do best with characters who are coming apart at the seams.”
“Sure, Marilyn Monroe was great, but she had to play a one-sided character, a vulnerable sex object. It was a real fantasy.”
Clayburgh also played in Bridesmaids that wasn’t yet launched.