Phoenix's mother, Arlyn Sharon (née Dunetz), was born in New York, to Jewish parents of Hungarian-Jewish and Russian-Jewish descent.

[3] Phoenix was a child actor, working with agent Iris Burton along with her brothers and sister at the age of two,[citation needed] and went on to have guest roles in Murder, She Wrote, Growing Pains (as a not-very-close friend of Ben Seaver), Swamp Thing, and Airwolf.

She appeared in the TV movie Kate's Secret and in Russkies, playing the younger sister of real-life brother Joaquin.

In 2002, Phoenix starred in a three-month run of This is Our Youth at the Garrick Theatre alongside Matt Damon and Casey Affleck.

[14] Phoenix filed a petition of divorce with the Superior Court of California in Los Angeles on August 1, 2017, citing "irreconcilable differences,"[14] and it was finalized that year.