The Joker's first appearance in Batman #1, 1940

The Joker has been Batman’s number one nemisis ever since his debut in Batman #1 spring of 1940, the dawn of the Golden Age of comics. 

One thing about the Joker that made him so eternal is that he came out fully developed. From the beginning he was a seditious killer with a theatrical flair. If anything they tamed his character down over the years.

The inspiration for the Joker came from young Batman ghost artist Jerry Robinson. Jerry Robinson said, "I knew that all great heroes had an anti-hero, and were stronger characters because they were pitted against strong antagonists." "I began to toss around ideas and somehow I thought, well, he's got a sense of humor - he's a joker. I immediately made an association with the joker playing card with that marvelous grinning face." "Then I made my first drawing of the Joker, a playing card with the Joker face on it."

"In that first meeting when I showed them that sketch of the Joker, Bill (Finger) said it reminded him of Conrad Veidt in The Man Who Laughs. That was the first mention of it...He can be credited and Bob (Kane) himself, we all played a role in it. The concept was mine. Bill finished that first script from my outline of the persona and what should happen in the first story. He wrote the script of that, so he really was co-creator, and Bob and I did the visuals, so Bob was also." remembers Robinson.

Bill Finger really shows off his talents in this incredible initial appearance of the Joker, depicting a homicidal maniac who takes glee in finding creative ways to kill his victims and confound the police for his own seditious amusement.

If anything I think this story really shows off what an incredible talent Bill Finger was. Here he really captures the essence of the maniacal killer all in just 11 pages. Over the years they have played with his original concept but it’s so strong that no matter what form the Joker takes, his original greatness seems to always manage to shine through.