The 'Los Angeles Times'reports that Spradlin died of natural causes at his cattle ranch in San Luis Obispo on Sunday.
Born in Oklahoma in 1920, Spradlin served in the Army Air Forces in China during World War II and worked as a lawyer before becoming rich as an independent oil producer.
He turned to acting in his 40s and used his real-life experience as an attorney, oilman and rancher to play men in charge.
Spradlin also directed John F. Kennedy's 1960 presidential campaign in Oklahoma and ran for mayor of Oklahoma City, unsuccessfully, in 1965.
Spradlin's grandson told reporters that "He brought a lot of what he had done in his life to what he did on the screen," adding that his grandfather had a lifelong love of language and could recite passages from Shakespeare and poetry until the end.
He appeared in dozens of TV series, mini-series and TV movies from the mid-60s onward, including 'Dragnet,' 'Gomer Pyle, U.S.M.C.,' 'Bonanza,' 'Rich Man, Poor Man -- Book II,' 'Columbo' and 'War and Remembrance.'
Spradlin's last TV role was in a 1996 episode of 'Dark Skies,' and his last movie role was as 'Washington Post' executive editor Ben Bradlee in 'Dick' (1999).
However, depsite his prolific TV career, Spradlin will best be remembered for two stand-out movie roles. In 'Apocalypse Now' he played the general who sends Martin Sheen's character up-river to find and kill Colonel Kurtz (Marlon Brando).
In 'The Godfather: Part II' he played the corrupt Nevada Senator Geary who tries to belittle the Corleone family by overcharging Michael (Al Pacino) for a gaming licence. The Corleones later blackmail Geary after he is found in bed with a murdered prostitute.
G.D. Spradlin is survived by his wife, Frances, two daughters and five grandchildren.