Rao is known for his path-breaking work in biographical films; He essayed the Tamil saint Thondaradippodi Alvar in the 1954 film "Vipra Narayana"; Tenali Rama in the 1956 film "Tenali Ramakrishna", which received the All India Certificate of Merit for Best Feature Film; Kalidas (the Sanskrit poet of Ujjain) in the 1960 film "Mahakavi Kalidasu"; the 12th Century Sanskrit poet Jayadeva of Odisha in the 1961 film "Bhakta Jayadeva"; the Kannada sculptor Amarashilpi Jakanachari in the 1964 film "Amara Shilpi Jakkanna"; the Marathi saint Tukaram in the 1971 film "Bhakta Tukaram"; Kabir in the 2006 film "Sri Ramadasu"; Valmiki in the 2009 film "Sri Rama Rajyam". Similarly, Rao played many famous mythological figures such as Lord Vishnu in "Chenchu Lakshmi"; Narada in "Bhookailas" and Arjuna in "Sri Krishnarjuna Yuddhamu".