Marlon Williams usually works at brother Shawn's newsstand at the Niedermeyer Building in the main lobby located near Pop's Diner, owned by their father, Pops Williams on the WB's TV series The Wayans Bros.. Oftentimes derided by Shawn for has irresponsibility, Marlon, nevertheless, is also ambitious, and aspirations of becoming an actor on stage or TV. At different times, Marlon has worked as a waiter, a failed TV sitcom and stage play actor, and taxicab driver, and with Pops in his diner, after losing his job at the newsstand after a fallout with Shawn, who everytime, winds up hiring Marlon back.
Usually the more impulsive brother of the two, Marlon usually serves as the comic foil to big brother Shawn, often at times getting himself, or Shawn into tight spots, as with the time Marlon accidentally joins the Army when he was to deliver a package to the Army base for Pops where an old Army nemesis (played by Ron O'Neal), now a Sergeant, is a drill instructor in the episode titled Saving Private Marlon. He and Shawn often compete for the affections of the ladies, with Marlon usually settling for Shawn's "sloppy seconds", and whoever else Shawn wouldn't even think of dating.
Marlon appears in one episode with a strong anti-drug abuse message, titled "The High Life". In a serious sequence, Marlon becomes dependent on downers after listening to the bad advice from a fellow aspiring actor accquaintance, Rico Davinci (played by Nick Spano) who supplies Marlon with them so that Marlon, who was nervous about an audition for a part in a play, would not be before the audition. In the middle of the audition, however, Marlon begins to break down, blowing the audition miserably, and it takes Shawn to help him go through withdrawal process cleansing himself of the amphetamines, in a display of the love between the two close brothers.