Who was the originator of this term?
 

The Living End.

Name of a Jesus and Mary Chain song, a live Hüsker Dü album, a movie, a band and their self titled album, a Jandek album, and the end title of the movie Rock Around the Clock.

That dude in Monster High who goes "I'm the living end, baby."

Oh and there's a movie called The Living End but it's named after the jamc song..

From Max Décharné's (excellent) 'Straight from the Fridge, Dad: A Dictionary of Hipster Slang'

THE LIVING END -
1. The best, superlative, righteous
2. The last straw, the limit 'Christ, he thought. This was the goddam living end. The kid in hot water again. Molly wise to Irene. He was sick and tired of the whole stinking rat race.' From the novel 'Run Tough, Run Hard,' Carson Bingham, 1961.

So it just started as a thing among hipsters and teens in the 50's?