Harmon worked as a
child model, and in 1987 won a
Seventeen modeling contest. She attended
Highland Park High School until 1990, where she was a member of the Highland Belles. She won a Spectrum Model Search contest shortly afterward, subsequently pursued a successful modeling career, and became well known in the early 1990s. She worked as a runway model for
Calvin Klein,
Giorgio Armani, and
Donna Karan and appeared on the covers of
ELLE,
Cosmopolitan, and
Esquire. She is signed with
IMG Models in
New York City. Harmon began acting in 1995 after being discovered on a plane by
David Hasselhoff. She then had a leading role in
Baywatch Nights and the short-lived
C-16: FBI. She also appeared in the 1997 film
Lawn Dogs, which received a limited theatrical release. In the late 1990s, Harmon became better known when she joined the
NBC series
Law & Order, playing ADA
Abbie Carmichael from 1998 to 2001. During this time, she also voiced
Barbara Gordon in the animated film
Batman Beyond: Return of the Joker, succeeding
Stockard Channing in the role. Harmon left
Law & Order to concentrate on her film career, saying that she preferred working in film to television. After appearing in the 2001
direct-to-video film
Good Advice, she had a supporting role in
Agent Cody Banks (2003), playing the
CIA handler of a teenage agent (
Frankie Muniz). In 2006, Harmon co-starred with
Cuba Gooding Jr. and
James Woods in the direct-to-DVD political suspense drama
End Game, and appeared as Rose in the acclaimed Western film
Seraphim Falls. In 2006, Harmon starred in an ABC
pilot Secrets of a Small Town, which did not go to series. She also starred in another failed television show on NBC,
Inconceivable, which was canceled after two episodes. The following year, she starred in another ABC pilot, ''
Women's Murder Club, which aired for thirteen episodes. Harmon was one of five actresses who posed discreetly nude for the May 2008 issue of Allure'' magazine, alongside
Gabrielle Union,
Zoe McLellan,
Jill Scott, and
Ana Ortiz.
In 2010, Harmon hosted an infomercial for "UpLiv", a stress-management program, and also appeared in an infomercial for Olay "Pro-X" wrinkle cream. From 2010 to 2016, she co-starred with Sasha Alexander in the TNT crime-drama series Rizzoli & Isles'', playing
Boston police detective Jane Rizzoli. The show premiered July 12, 2010. She directed the series' 100th episode. Harmon won Outstanding Female Actor in a Leading Role in a Drama Series for
Rizzoli & Isles at the 2012
Gracie Allen Awards, and also won a
People's Choice Award for Favorite Cable TV Actress in 2015. Harmon appeared in the music video for
Craig Morgan's "
This Ole Boy", released in January 2012. In July 2012, during promotions for a new season of
Rizzoli and Isles, Harmon revealed on
Conan O'Brien's
late night series that she was a fan of and very interested in playing a film version of
She-Hulk should such a film become available. In June 2021, Harmon signed a multi-picture development deal with
Lifetime. She hosted the documentary series
Cellmate Secrets and starred as Hazel King in
Buried in Barstow. ==Personal life==