In the 1990s, Mann kicked off a solo career, releasing three albums that garnered overwhelmingly positive reviews but failed to register on the sales radar. She had a minor college radio hit with the catchy "I Should Have Known" from 1993's "Whatever" and won some attention when "That's Just What You Are" was heard on Fox's "Melrose Place" in 1994 and proved a stand-out track on the series' popular soundtrack album. In 1996, her solo work made its big screen debut when the song "Wise Up" was featured in Cameron Crowe's romantic comedy "Jerry Maguire". "Amateur" from Mann's second solo effort "I'm With Stupid" was featured on the big screen in both 1997's "Picture Perfect" and the following year's "Sliding Doors". Getting more play in multiplexes than she had received on the radio in over a decade, Mann herself appeared on film with a cameo in "The Big Lebowski" (1998). That same year her music was featured in Susan Skoog's 1980s set coming-of-age drama "Whatever". Next Mann's song "You Could Make a Killing", (first featured on the 1995 release "I'm With Stupid") was the sound of heartless opportunistic youth in both "The Curve" (1998) and "Cruel Intentions" (1999).

Mann, whose somewhat reserved personal demeanor is in sharp contrast to the frank emotionalism of her songs, was drafted by admirer Paul Thomas Anderson to contribute music to his wrenching epic "Magnolia" (1999). Anderson (who has collaborated with Mann's husband musician Michael Penn on his previous efforts 1996's "Hard Eight" and 1997's "Boogie Nights") wove Mann's lush melodies and stirring lyrics into the film, even using her words ("Now that I've met you, would you object to never seeing me again?") for dialogue in a key scene. One of the episodic film's more memorable and daring segments has the cast each singing in turn lines of Mann's song "Wise Up". In the end, Mann's was the only music used in the film, with seven original compositions and a particularly haunting remake of "One", Harry Nilsson's classic ode to loneliness. This practically unheard of move was previously employed with legendary effect in Simon & Garfunkel's contribution to "The Graduate" (1967) and Cat Stevens' work for "Harold & Maude" (1971). Similarly evocative and transcendent, Mann's "Magnolia" score was widely heralded, and the positive reaction to her entry into the film world could make the singer-songwriter more apt to take on further scoring projects in the future, especially contrasted to the struggles she has had with the record industry.