Full name: His real name has never been given on the series.
Age: Never stated on the series.
Appearance: Like a lunatic jester. He dresses in the traditional "Harlequin" outfit, with alternations of red and blue; tights, poofy pants, and one of those jester hats. We rarely see him without the hat on but as it turns out, he's got no hair underneath it (heh heh). Generic black eyes, an inordinately large bill, and even more inordinately large teeth which, apparently, are fake.
First Appearance: "Whiffle While You Work".
Relationship to Darkwing: One of DW's main enemies.
Known relatives: None mentioned.
Occupation: Criminal; former toymaker; total lunatic; sometime-member of the Fearsome Five.
Special Skills: Is apparently a pretty good acrobat, as he likes to do flips; extremely good toymaker who evidently makes all his own toys - then makes them into weapons with lethal capabilities. O_o
Quirks: Laughs constantly; carries around a banana doll which he calls "Mr. Banana Brain" and makes it talk (sometimes in rhyme); as mentioned, likes to make his toys as dangerous as possible; has a special liking for giant novelty teeth.
Episodes: (I'll fill these in later)

The tragedy of Quackerjack's story is that it could happen to any of us. After all, the poor guy was a humble toymaker, dreaming only of bringing joy to the world through his creations. But Whiffle Boy took all of his business away. Who wouldn't go nuts from that? Okay, most people, probably. And I think even fewer would actually go nuts and become a supervillain over it. But, you know, I did get your attention, now didn't I?