The character joined the WJM newsroom as a meek, docile young lady who'd just moved from smalltown Roseburg, Minn. to big-city Minneapolis and was looking for a secretary's job.
Mr. Grant hired her as WJM's associate producer and she found her “family” among her co-workers and neighbors. And Mary developed into a confident woman.
Producer Ed. Weinberger explained Mary's transformation to TV Guide in a 1973 interview: "Instead of just reacting shyly to everyone else, she now yells at people and fights back. Instead of every-hair-in-place Mary of two years ago, she sometimes even is made to look lousy -- which all women do occasionally. In one segment, everything was going wrong for Mary that week. She had a red nose from a cold, her hair was askew, her dress didn't fit her. That's almost unheard of in television."
The show produced many historic TV moments, including the theme song and opening credits. Mary told the AAT the iconic hat toss was a “spur of the moment idea. We were out there in the middle of February in Minneapolis freezing. It was so cold I couldn't even speak.".
"They just wanted shots of me in action,” she said. “I was standing in front of a department store and they said, 'Run out to that intersection and throw your hat up in the air as though this is the happiest moment of your life.'”
Entertainment Weekly ranked Mary's hat toss as television's second greatest moment, and the city of Minneapolis honored the character in 2002 by erecting a bronze statue of Mary's tam toss where the scene was filmed.