He previously worked for West End Games and TSR, Inc., and designed products for Dungeons & Dragons, Star Wars, Alternity, Torg, Paranoia and Ghostbusters.

[3] Originally intending to pursue a career as a comic book artist, Slavicsek switched to journalism and communication at St. John's University.

[4] In 1987 the company secured the license to publish a Star Wars roleplaying game, a project which Slavicsek oversaw as an editor and developer.

[5]: 284  Peter Adkison left the third edition Dungeons & Dragons design work for Wizards of the Coast to Slavicsek and a group of other former employees of TSR.

[5]: 286  Hasbro told Wizards in December 2000 to cut 10% of its staff; Slavicsek was the "Director of Category" in charge of a team of roughly 60 people, and he made the decision to shut down the Los Angeles office of the remaining Last Unicorn Games division.

[5]: 317  By the time of the publication of the d20 edition of the Star Wars Roleplaying Game in 2000, Slavicsek held the title of Vice President and Director of RPG R&D for Wizards of the Coast.