The player who did the most to make it a mainstream part of the game is undoubted to be Julies Erving, known commonly as Dr. J.

He was the top player in the ABA and was a big factor in that league being absorbed into the NBA in 75. While other players had dunked before Dr. J he took it to a new level and used it as a regular part of his game not just for flash or intimidation. For an idea of his style here is a video of a few of his dunks: https://www.youtube.com/watch?v=zCTAaeZUUR8

Bob Kurland, a near-seven footer who played his college ball at Oklahoma State from 1942 to 1946, is considered the first player ever to dunk a basketball. Nicknamed "Foothills" due to his size, his first dunk was, according to him, instinctual.

"The ball happened to be under the basket. I got it up and stuffed it in," he said. "That started it, I guess. "What it was an unintentional accident. It wasn't planned, just a spontaneous play..."

His size was such that the NCAA had to institute a rule changes because of him. The defensive goaltending rule was created because he could easily block any shot headed for the rim.

He never played in the NBA, as it was only just starting at the time, but he did play AAU basketball successfully. He also won two Olympic gold medals in basketball.

And invented the dunk.