Ted Knight, as Ted Baxter, is actually a completely accidental instance of this. The role was originally conceived with Jack Cassidy in mind, but he turned it down. Cassidy did, however, appear in an early episode as Ted's equally egocentric brother, Hal.
Ear Worm: "Love is all around, no need to waste it..."
Executive Meddling: A common plot in-universe, as the station managers at WJM mess with the news show's format or try to make personnel changes. Somewhat subverted in that Ted's news show is so bad that the executives may have a point in wanting to change it.
Mary: [to Lou, after watching Ted on the news] That's the format you're so anxious to hang on to?
I Am Not Spock: Ted Knight hated the problems people had separating him from Ted Baxter. He had a hard time after the series as well.
Marathon Running: Nick@Nite's The Mary-thon, a week-long marathon (showing a season's worth of episodes each night) that introduced the series to the cable network's line-up in 1992.
Reality Subtext: One of the episodes from the final season is about Murray's frustration at being the only person in the group who hasn't won a Teddy Award. In real life, Gavin MacLeod was the only major cast member who never won an Emmy (he was never even nominated) and he later admitted his disappointment about this.
Star-Making Role: Pretty much everyone in the cast other than Mary Tyler Moore herself (and perhaps Betty White) can thank this show for first making them a household name.
Throw It In: When Moore filmed her famous hat-tossing scene in downtown Minneapolis, the camera caught an elderly woman scowling quizzically at her in the background. The woman was a local resident named Hazel Frederick, who happened to be walking down the street while shopping in the area and couldn't understand what this young woman was doing in the middle of a busy intersection. The producers decided the shot was too good not to use, and Frederick's face became an unintentionally iconic part of the show's opening.
Write Who You Know: Ted Baxter was actually inspired by real life anchorman Jerry Dunphy of CBS Los Angeles O&O KNXT, who later also provided the inspiration for Kent Brockman on Brooks's The Simpsons. note Ironically, however, in real life, Dunphy was actually a very competent, very professional anchorman. In fact, when he anchored KNXT's newscasts, titled The Big News for 6:00 PM newscasts, and 24 Hours for 11:00 PM newscasts, the programs generally attracted a quarter of Los Angeles television owners, ratings unheard of in the market. Indeed, Dunphy was so professional and so popular, that when KNXT unceremoniously fired him in 1975 in order to reshape their newscasts to contain a faster-paced, Eyewitness News type format, their ratings crashed to last place and have remained in last place to this very day. In addition, to add insult to injury, immediately after KNXT fired him, rival station KABC immediately hired him to be their chief anchorman, causing their news ratings to skyrocket to #1 in the process. Dunphy was also well loved behind the scenes as well. Near the end of his career, he was anchoring the main news for independent station KCAL, when he died of a heart attack on his way to work on May 20, 2002. On that day's 9:00 PM newscast, KCAL co-anchor Pat Harvey, fighting back tears, announced his death: "Los Angeles has forever changed tonight, because Jerry Dunphy will never come into your home again. Our beloved anchorman and friend has died. Jerry touched the lives of generations of Angelenos for more than 40 years; a beacon of truth and trust, and for all to turn to in good times and in bad."
What Could Have Been: Mary was originally going to be divorced, but the writers feared people would think she'd divorced Rob. Plus, executives back then didn't think a divorcée protagonist wouldn't appeal to many people.
Gavin MacLeod originally auditioned for the role of Lou Grant.
The role of Ted Baxter was written with Jack Cassidy in mind, but the actor wasn't interested in another sitcom commitment so soon after the failure of his critically acclaimed Short Runner sitcom He & She. He would eventually guest star as Ted's brother in one episode.