During his stint with the Times of India, he worked in Punjabi films including Sapani and Hindi films such as Woh Kaun Thi?, Shaheed, Main Shaadi Karne Chala and Teesri Manzil. Prem did not consider acting as a full-time profession in the early 1960s, but he kept trying to get roles in films due to his passion for acting. Among his early films he played Sukhdev in Shaheed, one of his rare positive leading roles. Prem had done four movies before Woh Kaun Thi?, a box office hit of 1964, had released. On the sets of Woh Kaun Thi? which had Manoj Kumar as lead hero, Prem met Manoj for the first time. Manoj offered Prem a positive role in Shaheed, for which Manoj was the presenter. During the shooting of Main Shadi Karne Chala someone suggested that he become a villain. He continued working with The Times of India, when he was already a part of box office hits like Nishan, Sikandar E Azam in 1965 and Sagaai, Mera Saaya in 1966. After Teesri Manzil and Upkaar, he was flooded with films as a villain.