Mary Phelps Jacob was born into a wealthy and socially prominent New York family. This privileged background provided her with access to education and cultural opportunities that would later shape her independent spirit and artistic pursuits. Her upbringing, however, also instilled in her a sense of the restrictive nature of societal norms for women, something she would later actively rebel against.

While preparing for a debutante ball, the young Mary Phelps Jacob found her whalebone corset cumbersome and unflattering under her sheer gown. Frustrated, she devised a solution using two handkerchiefs, ribbon, and cord – creating what became known as the 'backless brassiere'. Her innovation quickly gained popularity among her friends, offering a liberating alternative to the constricting corsets of the era. This ingenious invention would later be patented.