Haggerty's manager Terry Bomar confirmed to ABC News that Haggerty died early Friday morning.
Haggerty starred as Grizzly Adams in the 1974 movie "The Life and Times of Grizzly Adams" and the subsequent TV series of the same name, which ran from 1977 to 1978.
The actor also appeared in several other films and TV shows, including "Charlie's Angels" in 1981 and "The Love Boat" in 1983.
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ABC News contributed to this report.