Christopher Reeve

Film Deaths[]

Somewhere in Time (1980) [Richard Collier]: Dies of starvation in his apartment, after losing the will to live due to being separated from Jane Seymour through time. He appears as a spirit afterwards being reunited with Jane. (Thanks to Olenka and William)
Deathtrap (1982) [Clifford Anderson]: Killed (off-screen) during a struggle with Michael Caine; the film suddenly cuts from a scene of Michael and Christopher fighting to a scene of two different actors 'killing' each other in a stage play based on the storyline that Irene Worth is premiering.
Superman III (1983) [Evil Superman]: Evil Superman ceases when Clark Kent (also played by Reeve) gets the better of him in a fight. We only see Evil Superman disappear then learn they're now one person when Kent opens his shirt, revealing the super suit underneath.
Bump in the Night (1991) [Lawrence Muller]: Commits suicide by jumping out of a window rather than be arrested. (Thanks to Robert)
Village of the Damned (1995) [Alan Chaffee]: Killed in an explosion when he brings a bomb into the barn/classroom in order to destroy most of the alien children, while also struggling to keep them from reading his mind and finding out about the bomb. Only David survives, because his future partner was stillborn, and he became more human.

Saturday Night Live (April 6, 1985) [Guest Host]: Shot to death in a WWII-movie-spoof sketch. (Played for comic effect, obviously.) (Thanks to William)
Nightmare in the Daylight (1992 TV Movie) [Sean Farrell]: Shot to death by Jaclyn Smith.
Smallville: Sacred (2005) [Dr. Virgil Swann]: Dies (off-screen), shortly before the start of the episode; we are informed of his death when Tom Welling gets the news. (This episode was filmed after Christopher's real-life death.) (Thanks to Alex)