Kenner began working on her sanitary belt design. Her intention was to create a product that was more comfortable, reliable, and effective than the existing options available to women at the time. She experimented with different materials and designs to improve its functionality.

Mary Kenner successfully filed for a patent for her sanitary belt. This marked a significant achievement, making her one of the few African American women to hold a patent at the time. It was designed with an adjustable fit which protected clothing from leakage.

Despite the innovative nature of her invention, Kenner faced significant obstacles due to racial discrimination. A company initially interested in marketing her sanitary belt withdrew their offer upon discovering that she was African American. This unfortunate incident highlights the pervasive racial biases that existed in the business world during that era.

The patent for Mary Kenner's sanitary belt eventually expired. Without the financial resources to continue production and distribution independently, her invention did not achieve widespread commercial success during her lifetime.