Robert Keith

Robert Keith (1898 - 1966)

Film Deaths

Written on the Wind (1956) [Jaspar Hadley]: Dies of a heart attack.
The Lineup (1958) [Julian]: Shot to death in the back by Eli Wallach while pleading for his life.
Cimarron (1960) [Sam Pegler]: Killed in the Oklahoma Land Rush when Dawn Little Sky is forced to swerve her wagon to avoid running over Eddie Little Sky and Robert loses control of his wagon which crashes and as lies on the ground the following horses and wagon trample him and roll over his chest. (Thanks to Brian)

Studio One: Julius Caesar (1949) [Brutus]: Commits suicide by throwing himself on his sword. (I haven't seen this version, but I'm familiar with the play.)
The Alfred Hitchcock Hour: Final Escape (1964) [Doc]: Dies (off-screen) of a heart attack in prison; his body is shown afterwards when Edd Byrnes lights a match discovers that it's Robert's body that he's been buried with. (Edd had previously arranged an escape plan in which Edd would be buried with Nicholas Colasanto's body and Robert would later dig him up--unknown to Edd, Robert had died before Edd snuck into the morgue, so Edd was left buried alive with nobody to save him.)
The Twilight Zone: The Masks (1964) [Jason Foster]: Dies of old age/natural causes, with his family (Virginia Gregg, Brooke Hayward, Milton Selzer and Alan Sues) gathered by his bedside, while they're all wearing masks that reflect their personalities. His body is seen again when Willis Bouchey removes his mask (though unlike the others, whose faces have been magically altered to resemble their masks, his face remains unchanged).