Sadie Knowles devoted four decades of her life to local libraries and children.

Hired to work at the Sarnia Library in 1922, in  1931 Sadie was put in charge of the children's department. Sadie headed the children's department until her retirement in 1969. Glen Phillips commented in his book Sarnia: More Picture History, “Sadie's warm smile, friendly manner, and infectious enthusiasm combined to spark every child's imagination during ‘story hour'. She captivated her youthful audiences with lively tales of dragons, Arabian Knights, and distant, magical lands.”

Sadie was involved in other local organizations. She sat on the Sarnia Women's Conservation Art Association that was instrumental in bringing artwork by the Group of Seven to Sarnia. She was also involved in Canadian Girls in Training and St. George's Anglican Church. In 1978, Sadie was presented with a Queen's Jubilee Medal for her years of service.

She passed away July 26, 1984.