Alexander Richard Pettyfer was born in Hertfordshire, a county in southeastern England, and spent his early years in Windsor, a historic town located west of London. His mother, Lee Robinson, is an accomplished interior designer, and his father, Richard Pettyfer, is also an actor, having shared the screen with his son on several occasions. The couple's marriage did not last, and Alex's mother later remarried a property developer, Michael Ireland, with whom she had a younger son, James, who is a talented junior tennis player.
As a child, Alex began modeling for Gap's children's clothing line at the tender age of seven. He also appeared in various television commercials, further honing his skills in front of the camera. As he grew older, he modeled for the prestigious fashion brand Burberry, using the opportunity to fund his passion for traveling and exploring the world.
Throughout his education, Alex attended various private schools, where he discovered a love for performing in school plays. At the age of 13, he auditioned for the role of a lifetime in the television movie "Tom Brown's Schooldays" (2005),and his talent and dedication earned him the part. This early success paved the way for his breakthrough role at the age of 15, when he was cast as the titular character, Alex Rider, in the film "Stormbreaker" (2006),also known as "Alex Rider: Operation Stormbreaker." This critically acclaimed performance earned him a Young Artist Award nomination and an Empire Award nomination, solidifying his status as a rising star in the entertainment industry.