Actually, he started out with his own comic, something I wasn't aware of as a kid (because I encountered him in the Richie Rich digests); his solo title failed, so it became "Richie Rich and Jackie Jokers." I agree with everyone that there's something deeply weird about a little kid working as a Borscht Belt comedian, especially when his look-alike father seems to have pushed him into it -- don't they have child labor laws?
And yet as a child, I kind of liked the Jackie Jokers stuff, even though I knew even then that the writing wasn't any good and that Jackie's jokes were terrible. (It really was an indication of how little respect Harvey Comics had for kids that they thought we'd believe Jackie was a great comedian, even though he never had a funny joke.) I probably liked them because they were the only stories in those digests that took the focus off a) Richie's disgusting wealth and b) Richie preventing desperate, hungry people from stealing anything from his vast wealth.
So in addition to the stories mentioned on that page, I remember Richie and Jackie writing a script for a sci-fi comedy (Reggie Van Dough tried to steal it, but they fixed him), which consisted entirely of bad puns:
FUTURE JACKIE: Can I borrow your spaceship, Richie? I want to be a star on some star!
FUTURE RICHIE: How star-tling!
Okay, that doesn't even rise to the level of a bad pun.
There was also this story that featured a second show-biz kid, "Kool Katz" the musician with an overbearing Jewish mother. In this story, Kool's "Mama" had written a play called "Boy in the Big House," which she thought was a drama but everyone mistook it for a comedy. Richie produced it on Broadway with Jackie as the star, and it became a huge hit as a comedy, and Mama accepted it when she realized it was a hit.
BOY IN THE BIG HOUSE: Oh, what a fate, to be the Boy in the Big House! If only I had listened to my Mama and worn a sweater on windy days, this wouldn't have happened to me!
At least the dialogue was better than in Richie and Jackie's frickin' script.
And yes, I remember those movie and TV parodies with Jackie. I remember "Carry" (Jackie is forced by everyone to "carry" their books, until he uses his telekinetic powers to get even). I remember "Shirley and Laverne," a parody of "Laverne and Shirley." (Worst title parody ever.) And I remember "Sez-a-Who Street," featuring the Comic Book Monster, who ended the story by eating the whole comic book.
Yes, I screwed up my childhood, and all because I had nothing better to read on bus rides and boring assemblies.
If you can stand more of this, Scott Shaw! reviews a Jackie Jokers issue where Jackie meets Nixon and Kissinger.