There was a character from a science fiction series in the early 80's named Danny
Keener... initials were DMK (not entirely sure about the spelling).  I
need to know what show and a description of the character.

Thanks a lot!

I am certain that the character you're thinking of is Danny Mason
Kenner, also known by the initials he uses when playing video games,
DMK.

This character appears in "Night of the Comet." In the movie, most of
mankind has been wiped out by a comet. A couple of teenage girls have
adventures in the nearly deserted city of Los Angeles. One of the
girls enjoys playing video games, but is annoyed that someone with the
initials DMK has posted most of the high scores. At the very end of
the movie, we briefly meet a guy named Danny Mason Kenner, who is
obviously the "DMK" who won all those games.

Internet Movie Database: Night of the Comet (1984)
http://www.imdb.com/title/tt0087799/combined

Google Web Search: "night of the comet" dmk OR kenner
://www.google.com/search?hl=en&q=%22night+of+the+comet%22+dmk+OR+kenner

I hope this is precisely what you need to know. If this is not the
correct character, please request clarification; I'll be glad to offer
further assistance before you rate my answer.

Best regards,
pinkfreud

Perfect! This guy knows what he is talking about!