Karaszewski teamed up with his USC roommate Scott Alexander and sold the crime comedy "Homewreckers" to 20th-Century Fox for $300,000 in 1986, though the film was never produced. The team first made it to the big screen in 1990 with "Problem Child", which turned into a problem film. Karaszewski and Alexander had written it as a dark "Bad Seed" parody, but the studio turned it into one of the year's most reviled kiddie comedies. The two reluctantly agreed to pen "Problem Child 2" (1991), with similar results and damage to their budding careers.
In 1994, Tim Burton directed their script of "Ed Wood", with virtually no changes, and they had their first critical hit. An odd, touching and somewhat warped tribute to the so-called "World's Worst Director", the film managed to laugh both at and with Wood, and provided Martin Landau with a meaty, Oscar-winning role as the decrepit Bela Lugosi. With the success of "Ed Wood", Karaszewski and Alexander were able to sell an even more controversial biopic of the pornographic magazine publisher, "The People vs. Larry Flynt" (1996), produced by Oliver Stone and directed by Milos Forman. Described by Karaszewski as "Frank Capra with porn," the film takes an outrageously vile character and makes him a hero of sorts. Their script provided challenging, well-written roles for Woody Harrelson (as Flynt), Courtney Love (as his ill-fated wife) and Edward Norton (as his lawyer).
Karaszewski and Alexander also did uncredited work on two films. They relinquished credit on the animated "Cats Don't Dance" (1997), but unsuccessfully objected to being omitted from Burton's "Mars Attacks!" (1996), on which Jonathan Gems was listed as sole screenwriter.