Efrem Zimbalist Jr.

Film Deaths:

The Crowded Sky (1960) [Dale Heath]: Killed in a plane crash, along with Troy Donahue, when their plane collides with a commercial airliner.
The Reward (1965) [Frank Bryant]: Shot to death, along with Henry Silva, by Emilio Fernández.

Rawhide: The Last Order (1965) [Jeff McKeever]: As a lieutenant in a group of renegade Confederate soldiers Efrem is mortally wounded by Lawrence Dobkin shooting him in the back when he refuses to place Clint Eastwood before a firing squad.
Gargoyles: Revelations (1996; animated) [Mace Malone]: Dies (off-screen) of exhaustion/dehydration after being trapped in his own booby-trapped hotel. He is last seen frantically trying to escape, but series creator Greg Weisman has confirmed on his website that the Illuminati left him to die for his failure to keep Goliath (Keith David) from escaping.
Babylon 5: The Face of the Enemy (1997) [William Edgars]: Killed in his home by Walter Koenig's men. His body is seen when Jerry Doyle rushes in and discovers him dead.
Batman Beyond: Rebirth, Part 1 (1999; animated) [Alfred Pennyworth]: He is not heard or directly mentioned in the series, but his character from Batman: The Animated Series and The New Batman Adventures is believed to have died of old age/natural causes in the intervening twenty years.