The Doorknob is not particularly helpful, caring only about getting sleep. He is lazy, quite obviously, as a short cutscene is always played when approaching him that shows the Doorknob snoring. He does, however, offer some help, as he tells Sora that he is too big, and that he will need to drink the potion. He is also rather acerbic, as shown when Goofy offers a pleasurable "G'mornin" in Kingdom Hearts and he bluntly says, "Goodnight! I need a bit more sleep."
The Doorknob is, true to his name, a sentient, gold door handle. His escutcheon plate is shaped like an elongated trapezoid with a semi-circle bump on the bottom and a curly design on the top, giving the Doorknob the appearance of having a chin and hair, respectively. A gold screw on each bottom corner of the plate keeps the Doorknob attached to his door. He has close-set, beady yellow eyes and what seem to be black "eyebrows", though these may actually be engravings on the Doorknob's plate rather than hair. The Doorknob's prominent bulbous nose is actually the knob part of a doorknob, the part that is turned to open the door, something the Doorknob doesn't pretend to enjoy. His mouth is the keyhole part of a doorknob (as well as the Keyhole of Wonderland), though it is not fixed in place like it should be; the Doorknob has no problems moving his "lips" to talk.
Alice in Wonderland
Who Framed Roger Rabbit
The doorknob can be breifly spotted, right at the part where Eddie Valiant twists his nose and closes the door to a unfinished bathroom in order to get away from Lena Hyena.
House of Mouse
Kingdom Hearts series
The Doorknob appears in Kingdom Hearts, Kingdom Hearts: 358/2 Days, and Kingdom Hearts coded. The Doorknob's mouth contains the Keyhole to Wonderland.
Sora, Donald, and Goofy followed the White Rabbit into the Bizzare Room. As soon as they enter, they see that the White Rabbit has shrunk and ran through a small door. Sora and his friends look at the door and wonder how the White Rabbit got so small. Much to their surprise, the Doorknob starts talking and tells them to try the bottle on the table, then goes back to sleep. Much later, Sora comes back to the room and defeats the Trickmaster. The Doorknob wakes up after the battle and yawns to reveal Wonderland's Keyhole, which is inside of his mouth. Afterward, the Doorknob goes back to sleep.
Role in the series
The Doorknob reprises his role from KH and the movie, but doesn't join the Shell Louge Squad despite being a Wonderlandian. But how can he, he's a doorknob and is stuck on the door, although House of Mouse shows him being able to walk his door body, and, Scroopfan may have a change of heart for Doorknob if he feels he's ready.