Klári Tolnay (born Rózsi Tolnay) was born on 17 July 1914 in Budapest, as the daughter of István Tolnay and Eleonóra Siess. She spent her childhood in the small village of Mohora, Nógrád county, on the estate of her father. Finishing elementary school there, she continued secondary school studies in Balassagyarmat, two years at the school operated by Institutum Beatae Mariae Virginis in Nyíregyháza, finishing high school in Debrecen's School of Business. Singing and playing music since childhood, she followed the advice of newspaper Editor János Bókay, and auditioned herself to prominent actors of the time, Gábor Rajnai, Jenő Heltai, and Sándor Hevesi. After these early attempts were not followed by desired results, she was mentored by Béla Gaál, thus starting her career as a film Actress at the Hunnia Film Studio.