The sixth of seven children, Hunt was born in Chicago, on September 22, 1964. Her love of acting began in high school and, though she wanted to become a professional actor, her father pushed her toward nursing, the profession she pursued after graduation. Even after her father passed away while she was in nursing school, Hunt continued with the program and upon graduation worked in the oncology ward of Northwestern Memorial Hospital. Working with so many terminally ill cancer patients had a profound effect on her, inspiring her not to wait to pursue her original dream. While still working as a nurse, she landed roles in small plays and began studying at the Second City Improvisational Theater. She worked for a time with a different improv troupe before being invited to join Second City's touring company in 1986. Within a few weeks, she had proven to be such a gifted comedienne that she was promoted to the troupe's first string of performers.
Shortly after debuting in Rain Man, Hunt accepted an offer to work with Second City's Los Angeles-based troupe; two months later, she left the troupe and within a few days of her initial unemployment was offered the chance to star in a sitcom on NBC. However, the show, entitled Grand, lasted less than a season. She made a second attempt at television, playing Jonathan Winters' daughter on Davis Rules, but she again found herself unemployed when it was cancelled.
In 1992, Hunt made her first appearance on Late Night With David Letterman. The appearance proved to be an important juncture for Hunt as she not only charmed the irascible Letterman, but wowed the audience with her witty stories. Hunt became a personal friend of the talk show host and made frequent return visits. Around 1993, Letterman produced the short-lived CBS sitcom The Building, which Hunt had created and for which she penned 20 episodes. Hunt herself starred along with cronies from her Second City days; with the show's first airing, she became the first woman to write and star in her own series.
In film, Hunt had her first starring role in Beethoven (1992), followed by a cameo role as a White House tour guide in the romantic comedy Dave (1993). She has subsequently alternated between supporting and leading roles. One of her best-known parts was the sharp-tongued Laurel in Cameron Crowe's Jerry Maguire (1996). She also appeared in Frank Darabont's The Green Mile (1999) as the wife of a prison security guard (Tom Hanks).
In 2000, Hunt added feature film directing and screenwriting to her resume with Return to Me, a romantic comedy starring David Duchovny and Minnie Driver. Hunt also took on a supporting role in the film which went on to become a modest sleeper hit. After trying her hand behind the camera, in 2002 Hunt decided to take her fourth shot at the small screen (1995's The Bonnie Hunt Show was a flop too), producing and starring in ABC's Life With Bonnie. A mix of traditional sitcom and improv, the show proved to be a hit and netted the actress consecutive Best Actress Golden Globe nominations.
In the wake of the show's success, Hunt returned to film, starring alongside Steve Martin in 2003's Cheaper by the Dozen. The film saw Hunt play the mother of twelve children and proved to by quite a success, raking in well over $100 million at the box-office. A featured role in Tim Kirkman's episodic indie-drama Loggerheads preceded a trip back into the realm of Pixar magic when Hunt provided the voice of sexy Porche Sally in 2006's computer animation hit Cars. Hunt rejoined Pixar in 2010 to voice Dolly the doll in Toy Story 3, and reprised her role as Sally for Cars 2.