Origin

Edith Keeler was born in New York City in 1901.  She was later killed by a truck crossing the street.  After going to finishing school she became the founder of the 21st Street Mission.  It was here in 1930 that she met James Kirk and Spock who were traveling back into time to find Leonard McCoy.
 
Kirk and Keeler fell in love while he and Spock tried to locate Spock.  Unfortunately Spock discoverd that if Keeler lived the timeline would change wiping out the existence of the Federation in Kirks time.  Kirk saw Keeler walk in front of a truck and prevented McCoy form saving her to preserve the timeline.

Creation

Elizabeth Keeler was created for the original Star Trek television show.