The Emmy-nominated actress passed away Thursday night, according to her representatives.
"Our dear and beloved Glenne has indeed passed away. We are all incredibly saddened. Tremendous loss and are holding her family dear," the statement read.
Headly was shooting for Hulu's "Future Man," a comedy pilot from Seth Rogen, when she passed. Her cause of death was not yet determined.
Other credits, among many, include "Mr. Holland's Opus," "Dick Tracy," "The Joneses," and "Lonesome Dove." She also had recurring roles in "ER" and "Monk."
In 1979 Headly was recruited by Chicago's budding Steppenwolf Theatre, joining such fellow up-and-comers as Gary Sinise, Terry Kinney and John Malkovich, who would become her first husband. They divorced in 1988.
Headly is survived by husband Byron McCulloch and their son.
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The Associated Press contributed to this report.