Muaddi was born in Romania to a Jordanian father and a Romanian mother. Shortly after, her family relocated to Amman. Her parents split when she was six and she returned to Romania with her mother, where she spent most of her childhood. Muaddi recalls that by the time she was nine, she was determined to work in the fashion industry. After completing her studies at the European Institute of Design in Milan, she worked as an assistant stylist for Condé Nast, Vogue Italy, L'Uomo Vogue and then for GQ magazine in New York.