She appeared in various television commercials and made her film debut in The Cable Guy in 1996.
She and Paul Rudd play a married couple in the 2007 film Knocked Up and their story continues in the 2012 comedy This Is 40.
She was raised by a single mother in San Francisco. She married Apatow on June 9, 1997 after previously meeting on the set of The Cable Guy. She and Apatow have two daughters named Iris and Maude who play Mann's children in Knocked Up and This Is 40.