Lucasfilm president Kathleen Kennedy confirmed that Trainor, a long-time friend, died at home in Montecito, California, on May 20 at the age of 62.
Trainor got her start in the film business as a producer’s assistant on a number of movies including the 1979 Steven Spielberg film 1941, which her eventual husband, director Robert Zemeckis, wrote.
After the couple married in 1980, Zemeckis cast Trainor in her first film, Romancing The Stone, as the kidnapped sister of Kathleen Turner’s character.
In addition to a number of cameos in Zemeckis’s films, including Forrest Gump and Back To The Future, Trainor became a regular fixture in some of the biggest films of the 1980s. She played a police psychiatrist in Lethal Weapon and its sequels, a television reporter in Die Hard and the mother of two main characters in The Goonies. She also had a part in Ghostbusters II.
On the small screen, Trainor was a cast member on the short-lived series Relativity and had a recurring role on Roswell.
“Mare and I have been close since our days together as college room-mates, and she even provided the introduction to Steven Spielberg that jump-started my career,” Ms Kennedy said in a statement.
“She was a great actress, warm friend and generous spirit.”
Zemeckis and Trainor, who divorced in 2000, had one child, Alex Zemeckis.
A memorial service will be held on June 19 in Montecito.