Laura Petrie was originally supposed to be a minor character on The Dick Van Dyke Show — until Mary Tyler Moore auditioned

Sometimes, the characters that last forever in our memories begin their journey with the intention of only taking up a small amount of space. Such was the case for Laura Petrie, a loving wife and mother, quick as a whip with humor to match a comedy writer. 

But it turns out that the original plan wasn't for Laura to have such an expansive role as one of the main characters of The Dick Van Dyke Show. In an interview with The Courier, creator Carl Reiner said, "As I saw it originally, it was only a minor role. I thought she would just be there to greet Van Dyke when he came home at night and to serve him his dinner." What changed his mind and expanded the character, was actually Moore herself. Reiner stated, "Mary has fantastic dedication to her work, and we soon discovered we had accidentally stumbled onto a kid who could do great comedy if for no other reason than her relentless will to excel."

Moore saw it in a different way. She argued, "Dedication always sounds so noble. Maybe competitive instinct is a better term for it. Anyway, it's something deep inside me that I can't ignore. If you have it, you know what I mean. If you don't have it, well...maybe there's no way you can understand it."

Moore was recommended for the role of Laura Petrie by Danny Thomas, who had previously rejected her for the role of his daughter in his own series. Specifically, he told her, "You're a bit too sophisticated to play my daughter. Besides, with a beautiful little nose like yours, nobody would believe you belonged to me." However, Thomas was aware enough of Moore's talent that when he discovered that Carl Reiner was struggling to cast a role in his series, he told Reiner, "Look up that girl with the three names." Apparently, Reiner knew Moore was good for the show within a few minutes of meeting her.