She has Italian, Irish, Hungarian, German, and English ancestry. She wanted to be an actress when she was young. Her first job came at age 16 when she got the role of "Laurie Lewis" on All My Children (1970). Alex co-starred, with Logan Lerman & Brandon T. Jackson, in the role of 'Annabeth Chase" in the "Percy Jackson" movies, which were based on Rick Riordan's best-selling teen books.
She is best known for playing "Annabeth Chase" in the "Percy Jackson" film series and "Blake Gaines" in San Andreas. She starred in the films, Texas Chainsaw 3D and Hall Pass, and has guest-starred on TV series, including White Collar, It's Always Sunny in Philadelphia, True Detective, and American Horror Story: Hotel.
In February 2017, Henry Cavill announced via his Facebook and Instagram social media accounts that Daddario had joined him and Sir Ben Kingsley in the psychological thriller Nomis, which began filming by the end of that month in Winnipeg, Canada.
She has also lent her voice for I Spy School Days. She has strikingly blue bold eyes.