Wally was inspired by a coworker of creator Scott Adams at Pacific Bell. In Seven Years of Highly Defective People and What Would Wally Do, Adams explained that his co-worker at Pacific Bell wanted to avail himself of the generous severance packages being offered by the company during a period of downsizing, because he was told there was no future for him at the company; he thus embarked on a mission to get fired. Adams was inspired by this co-worker's serious dedication toward this goal, and the concept of a completely shameless employee with no sense of loyalty became Wally.

Another story from Adams has him based on a co-worker who made some sort of error, not huge enough to get him fired, but huge enough to wreck any chance of ever advancing in the company. Without any incentive to work hard, he began to do as little work as he could, and successfully managed to stay with the company for years.

In the animated series, we discover that Wally was once a great programmer. As described by a female employee in a flashback "He just programmed an entire database from scratch!" He is used later in the episode to solve the Y2K bug while hypnotized. When the hypnosis wears off; Wally claims he is more "soiled" than usual and ask if he has been working.

Due to his obsession with coffee, Wally's idea of "work" is simply carrying around a cup of the beverage, of which he drinks hundreds of cups a day, somehow without succumbing to caffeine overdose. It's made clear that he does not drink decaffeinated coffee, furthering the theory that Wally is some kind of non-human being. In one comic strip, he said (very unemotionally) that someone found asbestos in the ceiling of their building. He was wearing a breathing mask over his face, and if watched closely, his coffee cup was wearing one too. When Alice asked why he still worked at the company after making money on the stock market, he claims that he doesn't know how to make coffee.

He also has a notable lack of hygiene. He owns only one white shirt, and never washes it, because it's covered in white toothpaste stains that cannot be seen, and always smells minty.

Wally has no fingerprints, pulse, DNA, body heat, or the like. The lack of pulse may be the reason that he does not die from caffeine overdose, as death is usually from ventricular fibrillation. He reveals that his ancestors selectively bred to leave no such means of identification, and cites their reason as being "we prefer to ask why not" [as opposed to asking why].

Wally enjoys viewing pornographic web sites, as indicated in a couple of strips. His personal life is a bit odd; for example, he has a veterinarian for a doctor, fed a tree coffee and shredded memos, causing its growth to skyrocket to the roof, and he once started taking "Yoda" classes in the belief that they were yoga classes. In early 2008 Wally was fired for printing a cartoon criticizing the Pointy-Haired Boss. However, he was rehired after hiring Bob the dinosaur to beat the boss with his own suit.