Socialite and reality television personality best known as the star of the short-lived series High Society, which aired in 2010 on The CW television network. The series showcased Mortimer's exclusive New York social circle. In 2017, she joined the cast of Real Housewives of New York City.
She studied art history at Columbia University in New York.
In 2012, Simon & Schuster published her debut book, Southern Charm.
She was raised by real estate executive George Riley Mercer, Jr. and designer Dale Tatum Mercer. She married and divorced Robert Livingston Mortimer.
She appeared on The CW series Gossip Girl, which starred Leighton Meester.