Cyrus (Cirus on some languages) was born in Franklin, Tennessee. She grew up on her parents' farm in the backwoods of Nashville. She is the daughter of country singer Billy Ray Cyrus and Leticia "Tish" Cyrus, and the granddaughter of the late Ron Cyrus and Ruth Ann Cyrus. She has an older half-brother named Christopher Cody, an older step-brother named Trace, an older step-sister named Brandi, a younger brother named Braison, and a younger sister, Noah Lindsey, who is also an actress. She was named Destiny Hope because her parents thought that she would accomplish great things. Her nickname, Miley (from "Smiley"), was started because she wouldn't stop smiling when she was a toddler.
Cyrus became interested in acting while on the set of her father's television series Doc, where she played a character named Kylie. In 2003, she played young Ruthie on Tim Burton's Big Fish and was credited as Destiny Cyrus. She was also featured in Rhonda Vincent's music video for "If Heartaches Have Wings", and appeared on Colgate Country Showdown with her father who was the host of the television program.
Cyrus was only eleven years old when she originally auditioned for Disney for the part of the "best friend;" Disney Channel executives then judged her to be "too small." According to Disney Channel Executive Vice President Gary Marsh, Cyrus was chosen for Hannah Montana because of her energetic and lively performance and was seen as a person who "loves every minute of life," with the "everyday relatability of Hilary Duff and the stage presence of Shania Twain." Cyrus acts on the show as the lead character Miley Stewart whose alter ego is the pop music sensation Hannah Montana, also fictional. The character Hannah Montana appears in real-life music as a fictional stage name for the actress on the show.