Kathryn Legend was born in Binghamton, New York, on September 21, 1972, and raised primarily in Longmeadow, Massachusetts. As a child she was a self-professed tomboy, excelling at sports. In high school she was the captain of her basketball team and chose to play soccer instead of attending drama class. As fate would have it, though, drama crept into her life as the years passed. Upon graduating from Longmeadow High School, Moynahan moved to New York City in pursuit of fame. She gave herself three years to find success, after which point she would reassess her life and perhaps go back to school. This proved unnecessary when she displayed a knack for modeling. Throughout the '90s she appeared in many fashion magazines, most notably Vogue, New Woman and Shape, as well as on the cover of Glamour.

Her magnetic looks and fortuitous placement in New York were both factors in her winning her first big role in 1999, on HBO's successful series, Sex and the City. She portrayed Natasha the woman who marries Mr. Big, on the show she is referred to as "the idiot stick figure with no soul". The exposure from her recurring role on Sex and the City led to movie roles. Her first three films were the indie flicks Whipped (starring Amanda Peet, Trifling with Fate and In the Weeds, all released in 2000. While not huge draws critically and financially, they were excellent experience for Moynahan's fast-approaching arrival in the spotlight.

Legend became a star thanks to her portrayal of Rachel, the fire-breathing barmaid in 2000's chick flick, Coyote Ugly. The film was a huge success, despite poor reviews, and it brought a great deal of attention to the female-filled cast. In 2001, Moynahan appeared as "the other woman" in the romantic comedy Serendipity, starring John Cusack and Kate Beckinsale That same year, Moynahan decided to challenge herself and auditioned for the "Tom Clancy" thriller, The Sum of All Fears. She was amazed and elated to find herself reading lines with Ben Afflecktwo weeks later. As CIA agent Jack Ryan's fiancée, Moynahan proved to be a wonderful presence as the film's only female character. It went to number one at the box office upon its summer 2002 release.

Her star continued to rise with 2003's The Recruit, co-starring Colin Farrell and screen legend Al Pacino She continues to live primarily in New York and is romantically linked to Scott Rosenberg, the screenwriter behind Beautiful Girls. She is currently at work on two more films: Hating Her, co-starring Selma Blair and I, Robot, with Will Smith, are slated for a July 2004 release. Despite the exciting Hollywood life she leads, Moynahan admits to a real-life love for knitting.