Tinsley Mortimer was born Tinsley Randolph Mercer in Richmond, Virginia to George and Dale Tatum Mercer. Her great-grandmother’s maiden surname was Tinsley; her middle name Randolph is a reference to her ancestor Thomas Jefferson; and their family is descended from John Mercer, the writer of the first Code of Virginia. She spent her childhood at Graymont, the Mercer family house in Richmond. Tinsley was presented at the Bal du Bois and led that debutante ball with her only sister Dabney Winston Mercer.

She showed an intense aptitude in tennis, having been nationally ranked, and was trained in Florida by Nick Bollettieri. She finished her secondary education at The Lawrenceville School in New Jersey. She graduated from Columbia College of Columbia University with a baccalaureate degree in art history.

Tinsley stayed in New York and went to work at Vogue, where she was the assistant of editor Amy Astley, and left her post there to plan events for Harrison & Shriftman until marrying her high school sweetheart Robert Livingston Mortimer, also known as Topper, in 2002.

Her husband is the son of Senga and John Jay Mortimer. His family is considered one of New York’s oldest, establishing themselves in the state in the seventeenth century. They are descended from the colonial leader Robert Livingston; John Jay, the first chief justice of the Supreme Court; and Henry Morgan Tilford, a former president of Standard Oil of California. Topper is a hedge fund executive at Guggenheim Partners.

Beyond being New York’s preeminent socialite, Tinsley is a fashion designer. She launched her own handbag line, Samantha Thavasa by Tinsley Mortimer, in winter 2006 with the American flagship store in her very own neighborhood, the Upper East Side of New York. In summer 2007, she was installed as the beauty ambassador of Christian Dior. In fall 2007, she introduced her first clothing collection, Riccimie by Tinsley Mortimer, which is sold exclusively in Japan.