Leslie Mann was born on March 26, 1972, in San Francisco, California, and grew up in Newport Beach. Raised by her mother, Janet Ann Ayres, who worked in design and quality programs, she had a close-knit family despite having no relationship with her father.

She has two siblings and three older step-brothers. Leslie was very shy as a child, but she found her passion for acting in high school and went on to study at the Joanne Baron / D.W. Brown Acting Studio and with the comedy improv troupe The Groundlings. She attended college but dropped out before graduating to pursue her acting career.

Leslie Mann began her career at the age of 18, appearing in various television commercials. Her big break came in 1996 when she starred in "The Cable Guy," where she met her future husband, Judd Apatow, who was a producer on the film.

They married in 1997 and have two daughters, Maude and Iris Apatow. Leslie's career took off with roles in films like "George of the Jungle" (1997), "Big Daddy" (1999), "The 40-Year-Old Virgin" (2005), and "Knocked Up" (2007). She has often collaborated with her husband, appearing in films like "Funny People" (2009) and "This Is 40" (2012).

Leslie Mann is known for her comedic timing and has been referred to as the "reigning queen of mom-coms." Her performances have earned her critical acclaim and several award nominations.

She has been nominated for a "Best Supporting Actress" award by the Chicago Film Critics Association for her role in "Knocked Up" and has received praise for her work in "Funny People" and "This Is 40."