Michelle Lynn Monaghan was born on March 23, 1976, in Winthrop, Iowa. She is the youngest of three children and the only daughter of Sharon and Robert John Monaghan. After graduating from high school in Iowa, she studied journalism for three years at Chicago's Columbia College. In order to pay for college, she took a job as a model. In 1999, she quit college and moved to New York to work full-time as a fashion model. She traveled the world doing stints on the runways in Milan, Singapore, Tokyo, and Hong Kong, and also enjoyed appearances in a number magazines and catalogs.

In 2000, she made her TV debut in two episodes of Young Americans, then appeared in Law & Order: Special Victims Unit. She made her big screen debut with a small role of Henrietta in Perfume. Monaghan shot to fame in 2002 when she co-starred as Kimberly Woods for one season on the TV series Boston Public. After appearances in several supporting roles, she starred opposite Robert Downey Jr. and Val Kilmer in the black comedy Kiss Kiss Bang Bang. Later in 2005, Monaghan was filming in China, Italy, and the United States on Mission: Impossible III, as the female lead opposite Tom Cruise.

In August of 2005, in Sydney, Australia, Michelle Monaghan married her long-time sweetheart, Peter White, a New York based graphic designer, whom she met at a Manhattan party five years earlier.
Grew up in the small town of Winthrop, near Cedar Rapids in northeast Iowa. Studied journalism at Chicago's Columbia College. She had scenes deleted from Constantine and Syriana. Moved to New York in 1999. Is married to an Australian graphic designer Peter White. Has two older brothers. In Kiss Kiss Bang Bang, she plays an actress who did a commercial for a beer called Genaro's. In Gone Baby Gone she plays a character named Angie Gennaro.