There isn't a single, definitive author of this saying. It's likely to have been a popular expression passed down through generations or shared across cultures.
However, there are a few possible origins:
* It could be a variation of a quote by Thomas Carlyle: "The fruit of life is character: and character is formed by the daily acts of the will." While not exactly the same, it shares the sentiment of focusing on living well each day.
* It could be a phrase used in a specific context, but with no identifiable author. It might have originated in a religious sermon, a self-help book, or even a popular movie or TV show.
* It could also be a collective wisdom that developed over time and has been repeated and adapted by different people throughout history.
Regardless of its origin, the message of "Live one day at a time and make it a masterpiece" is a powerful reminder to appreciate each day and make the most of it.