Prakash began his television career with Doordarshan serials such as "Bisilu Kudure" (Kannada) and "Guddada Bhootha" (Tulu and Kannada). He later took up supporting roles in Kannada films such as "Ramachari", "Ranadheera", "Nishkarsha" and "Lockup Death". He was noticed for his dialogue delivery and histrionics. His breakthrough role came in "Harakeya Kuri", directed by K. S. L. Swamy starring Vishnuvardhan, with whom he had acted in other films such as "Mithileya Seetheyaru", "Muthina Haara" and "Nishkarsha". His performance was noticed by Geetha, the lead heroine of the film, who introduced Prakash to her mentor K. Balachander, a Tamil director. He acted under the screen name "Prakash Rai" in Kannada films and was given the name "Prakash Raj" by K. Balachander for his debut Tamil film "Duet", which saw him playing his first major role.