https://www.metv.com/stories/donny-most-helped-flesh-out-ralph-mouth-into-a-fuller-character

The bubble gum was mostly Most!

It turns out that the character of Fonzie was partially based off of Garry Marshall's childhood friends (https://www.metv.com/stories/it-turns-out-that-the-character-of-fonzie-was-partially-based-off-of-garry-marshalls-childhood-friends)

The character who was just too cool actually has some roots in reality.