Complex sentence: However, his film as a dialogue writer was K. Vishwanath's Siri Siri Muvva in the year 1977, was a blockbuster hit with which he got firm footing in Telugu cinema industry and since then never looked back.
Split into simpler sentences: However, his first film as a dialogue writer was K. Vishwanath's Siri Siri Muvva in the year 1977. With the stupendous success of this film, he got firm footing in Telugu cinema industry and never looked back.