Ludwig was born in Vancouver, British Columbia. He has three younger siblings: a sister and brother named Nicholas and Natalie, who are twins, and a younger sister, Sophia. His mother, Sharlene (née Martin), is a former actress, and his father, Harald Horst Ludwig, is a businessman. Ludwig was drawn to the profession, saying in an interview: "I have a big imagination. I love performing. " Yet, despite his mother's early career as an actress, Ludwig had to convince his parents to support his desire to pursue a career as a child actor. His parents believed that child actors "can get sucked into a life that isn't reality. " Ludwig is enrolled as a theatre major at the University of Southern California where he is in the Phi Kappa Psi fraternity, and lives full-time in Los Angeles.