The actress, who began her acting career in her '70s, died on December 20, said The Hollywood Reporter.
In Alexander Payne's "Nebraska", she played newspaper editor Peg Nagy.
McEwan had a recurring role on HBO's "Getting On", and also had appeared in the recent film "Moments of Clarity" and completed work on the upcoming indie "The Boonville Redemption".
McEwan, who was born in Santa Monica on April 23, 1934, studied acting at Los Angeles City College and later at UCLA, where she met Guillermo McEwan, then a medical student.
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After a subsequent move to Temple, Texas, and raising a family, she continued to act in local theater and was on the board of directors for the Temple Civic Theatre.
She also earned a master's degree in Spanish from UC Irvine and taught there for several years before becoming a criminal court Spanish interpreter for nearly 30 years.
After her husband, a gastroenterologist, retired about 10 years ago, she began taking acting lessons and soon started getting roles in low-budget films and on television shows such as "New Girl" and "Parks and Recreation".
"She believed that everyone tries to do their best within their abilities, so there is no reason to be negative."
McEwan is survived by her sons Carlos and William and her grandchildren Lynsey, Ian and Ellis McEwan. Her husband, Guillermo McEwan, died in 2009. Services are pending.