Entering the Malayalam film industry in 1965, T Hariharan has gone on to direct over 50 Malayalam films, many of which were successful both commercially and critically. His films, largely set against the backdrop of the cultural and social facets of Keralite society, depict the complexities of social issues and human relationships. His films such as Babumon (1975), Sarapancharam (1979), Panchagni (1986), Nakhakshathangal (1986), Amrutham Gamaya (1987), Oru Vadakkan Veeragatha (1989), Sargam (1992), Parinayam (1994) and Pazhassi Raja (2009) have come in for considerable critical acclaim. Sargam (1993) won him the Kerala State Award for Best Director and also bagged the National Film Award for Best Popular Film Providing Wholesome Entertainment, also receiving a special honour at the Fukuoka and Swiss film festivals. While Parinayam won the National Film Award for Best Film on Other Social Issues and participated in film festivals across the world, Ennu Swantham Janakikutty (1998) was the inaugural film at the Korean film festival (2000), and also participated in the London film festival (2000). Hariharan was also conferred a Diploma by the Pyongyang Film Festival of North Korea for Oru Vadakkan Veeragatha. His films also won multiple Filmfare and Ramu Kariat Awards. In 2020, he was awarded Kerala government's highest honour for contributions to Malayalam cinema, the J. C. Daniel Award. He has also nurtured numerous actors in the course of his career, including Vidhubala, Jayan, Madhavi, Geetha, Murali, Monisha, Vineeth, Saleema, Manoj K.Jayan, Mohini and Jomol.
After studying at St. Thomas College, Thrissur and Universal Arts College, Kozhikode,he worked as a high school teacher. The myriad colours of celluloid attracted him towards films. Reaching Chennai, he was unable to meet K S Sethumadhavan but, on the advice of his actor friend Bahadur, contacted director P B Unni, who permitted him to join his sets as an assistant director. He worked as an assistant director to M. Krishnan Nair, and went on to make his directorial debut with Ladies Hostel (1973). In the following years, he went on to make films like Babumon (1975), abox office hit of the black and white era, Panchami (1976) which gave actor Jayan his first major break in Malayalam cinema, and Sarapanjaram (1979) which became a blockbuster also starring Jayan and Sheela. This film propelled its hero Jayan into the superstar league. His historical epic Pazhassi Raja (2009) is based on the life of Kerala Varma Pazhassi Raja, the first revolutionary who rose against the British East India Company. More recently, he and writer M. T. Vasudevan Nair teamed up with young talented actor Indrajith to make the drama thriller Ezhamathe Varavu (2013).
Among the many awards T Hariharan has received are Filmfare awards for Best Director for Pazhassi Raja, Best Director for Parinayam, Best Director for Panchagni and the Filmfare Award for Lifetime Achievement in 2019. He has also been conferred the Prem Nazir Award and the V. Shantaram Award.
A master filmmaker, T Hariharan has been consistently engaged in perfecting the craft of filmmaking over more than three decades.