Ephron was born in New York City, the second eldest of four daughters of screenwriters Phoebe and Henry Ephron. Her movies include You’ve Got Mail, The Sisterhood of the Traveling Pants, Hanging Up (based on her novel), and Michael. She has written novels for adults (Hanging Up, The Lion Is In and the recent Siracusa) and teenagers (Frannie in Pieces and The Girl with the Mermaid Hair), books of humor (How to Eat Like a Child), and essays.

In 2011, she won an Athena Film Festival award for creativity and panache as a screenwriter

Ephron collaborated with her elder sister, Nora, on Love, Loss, and What I Wore, which ran for over two and a half years Off-Broadway. It has played in cities across the U.S., as well as in cities around the world, including Paris, Rio de Janeiro, Cape Town, Manila, and Sydney