David Day is the comic book artist brother of Gene and Dan Day. Like his brother Dan, he broke into the industry not long after Gene's death. His main contribution through the 1980s was working with his brother Dan on Cases of Sherlock Holmes. Other titles he worked on included Deadworld and Doctor Strange, Sorcerer Supreme.

His only Star Trek credit is cover art for Malibu Comics' 7th issue of their DS9 series, "Working Vacation", which he did with his brother Dan.