Marigold was born on TA 2983 (SR 1383). She youngest child of Hamfast Gamgee (The Gaffer) and Bell Goodchild. She was Samwise's younger sister. Marigold had four other siblings; Hamson, Halfred, Daisy, and May. Her brother Samwise Gamgee would be known as one of the most famous Hobbits in the Shire, and even all of Middle-earth since Frodo and Bilbo left Middle-earth to live out the rest of their life in Valinor.
She later on came to marry Tolman Cotton, a good family friend who was three years her senior. She was also good friends with her husband's sister, Rosie, who would later go on to marry Sam. Although it was never mentioned, Marigold most likely had children of her own.