Scruffy

Scruffy is the janitor at Planet Express and is the only person working for Planet Express who isn't a primary character. He reads pornography, and believes in his company, which somehow got him to own 40,000 shares of Planet Express while everyone else had 10,000. The other members of staff only see him occasionally, and rarely recognize him when they do. Sometimes he doesn't recognize them, either. Scruffy has indicated that he's been to prison.

Scruffy was originally just a background character seen working various jobs. However writers brought him in on the murder scene of Anthology of Interest I because they were running out of non-dead characters. From there his permanent role as the Janitor of Planet Express was cemented when he was brought back in later episodes without changing jobs.

Trivia

 * The first time he appeared, he didn't speak, and his moustache and hat colors were reversed.
 * Scruffy puts cameras up in every room in Futurama Returns
 * A comment made by Fry in The Luck of the Fryrish ("I didn't reveal the clover's location to anyone. Not even to Scruffy!") suggests that the two may have become close friends. But, at the time, this was more likely to be a pun on the fact that everyone always seem not to know who Scruffy is. However, in  Fry is shown to keep two of Scruffy's numbers, vs. one of everyone else's. This seems to extend the joke even further.
 * The Sting suggests he might be Scottish.
 * He had a career at Le Spa.
 * He also worked as a roadie for the Beastie Boys.
 * His hair turned gray prior to (or during) Anthology of Interest I, this is also when his name and job were confirmed. The hair and hat colour alternates between old and new during that episode.
 * Scruffy is regularly seen with adult magazines, he reads the articles, such as National Pornagraphic.
 * Has yet to complete his masters in Theoretical Janitorial Science.
 * Scruffy's character is based on Billy Bob Thorton's character (Karl Childers) in the movie Sling Blade
 * Scruffy was named after a bar in Venice called Scruffy O'Shea's
 * The October page of the 2008 Futurama wall calendar states that his last name is "Scruffington", this may not be canon.
 * Scruffy often refers to himself in the third person when he talks.
 * Has both a home and cell phone available to be called on Fry's cell phone in The Beast with a Billion Backs.
 * In Bender's Game, he became a person who apparently cleans up after the Centaurs.