Sweeney was raised in Los Angeles and is the second child of three. Making her television debut in a Kodak commercial at the age of 5, she soon began landing roles in television. As a teenager, she started portraying 'Sami' Brady on Days of Our Lives, where she has achieved many awards.

When she's not acting, Alison enjoys keeping active by kickboxing, horseback riding, swimming, and water-skiing. Sweeney is also an accomplished author. Her book, All the Days of My Life (So Far), was published in 2004 to critical acclaim. The book gives readers a glimpse into Sweeney's personal life by describing her experience as a child actor, life on the set of Days of Our Lives, painful high school memories, and the struggle to lose weight and keep it off.

Alison lives in Los Angeles with her husband Dave and son, Benjamin. Alison and Dave had a baby girl January 12 2009, Megan Hope, who weighed in at 6 lbs, 7 oz.

Days of Our Lives - Samantha "Sami" Brady (January 6th, 1993 to October 2014) Dual role - Colleen Brady (Monday July 9 - September 2007 - for flashbacks only) Return October 12 - Present)
A Brand New Life - Christy McCray (1989)
Family Man - Rosie Tobin (1988)
You Ruined My Life - School Girl #1 (1987)

Daytime Emmys Nominee, Outstanding Lead Actor (2015)
Daytime Emmys Pre-Nomination, Outstanding Lead Actor (2005, 2006)
Daytime Emmys Pre-Nomination, Outstanding Supporting Actor (2004)
Soap Opera Digest Award as Outstanding Younger Lead Actress.
Soap Opera Digest Award Four times (1996, 1998, 1999 and 2001)
Daytime Emmy - 'America's Favorite Villain.'