She is best known for playing a young Amy Adams in the Ron Howard film Hillbilly Elegy and for playing Lizzie Saltzman on seasons 7 & 8 of the CW's hit series The Vampire Diaries. Tierney is a fraternal triplet with Lily Rose & Miley and started her career as an infant doing print and commercial work. She is one of 7 children. There are her sisters, Lily Rose & Miley as well as a younger brother named Jaxon, and 2 older step-brothers and an older step-sister. Her sister, Lily Rose, is also an actress who played her twin sister Josie Saltzman on The Vampire Diaries.
