The last episode of the first season of all three of Aaron Sorkin's TV shows (The West Wing (1999), Sports Night (1998), and Studio 60 on the Sunset Strip (2006)), as well as the series finale of "The Newsroom" (2012), is titled "What Kind of Day Has It Been?"
The show was finally canceled when Aaron Sorkin decided to concentrate on his other show, The West Wing (1999). Despite low ratings on ABC, it got several attractive offers to continue on cable TV. All the deals included Sorkin as a writer, but Sorkin declined.
When Robert Guillaume suffered a real-life stroke, it was added to the story-line. His character, managing editor Isaac Jaffe, also had a stroke.
Originally conceived as a movie. Aaron Sorkin could not devise a coherent plot, but it fit the episodic nature of television.
The character of Casey is loosely based on former ESPN SportsCenter anchor Craig Kilborn.
According to Peter Krause, ABC tried really hard to change the show. They couldn't make every change they demanded because Aaron Sorkin and Thomas Schlamme fought back.
Clark Gregg was offered one of the lead roles. He had to turn it down because he was working on the pre-production of What Lies Beneath (2000). Gregg ended up playing the recurring role of The Stranger.
The tapes and decks used on the show are U-Matic (aka 3/4") format, which would have been very out-of-date in the late 1990s. At the time, the standard would have been Betacam. U-Matic equipment looks very much like Betacam equipment, and would have been much cheaper, especially for use as a prop.
During one episode, Dan shakes writer's block by reminding himself why he got into writing in the first place - to impress women. Josh Charles, who plays Dan Rydell, was also in Dead Poets Society (1989) in which Josh's character wrote poetry also to woo a woman.