Upon completing his schooling, he graduated with a degree in commerce from the Ramakrishna Mission Vivekananda College, affiliated to the Madras University.

[15][16] In 1995, Mani Ratnam was wounded and hospitalised after homemade bombs were thrown at his home by attackers, suspected by police as Islamic extremists, in the wake of opposition to his film Bombay which portrayed the romance of a Hindu man with a Muslim woman.

Mani Ratnam, Ravi Shankar and another friend Raman, son of filmmaker S. Balachander, worked on the script of the film.

Although not impressed with many of the films made in Tamil cinema, he was "amazed" at Bharathiraja's 16 Vayathinile (1977), K. Balachander's Apoorva Raagangal (1975), and Mahendran's Mullum Malarum (1978) and Uthiripookkal (1979).

During this time, he befriended a group of people namely P. C. Sreeram, Santhana Bharathi, and P. Vasu, who shared his interest of entering into the film industry.

[20] He managed to get other crew members B. Lenin (for Film editing), Thota Tharani (for art direction) and Ilaiyaraaja (for composer music), all leading craftsmen in their respective fields.

Although an average grosser at the box-office, the film fetched Mani Ratnam the Best Screenplay Award from the Karnataka State Government for the year 1983.

[12] Following this, he entered Tamil cinema when G. Thyagarajan of Sathya Jyothi Films offered him a chance to direct Pagal Nilavu (1985).

[21][27] In 1987, Mani directed Nayakan starring Kamal Haasan, and the film became a huge success and brought him recognition at the national level.

[37] The film deals with the story of half-brothers played by Prabhu and Karthik[25] and is notable for its use of new techniques in camera framework, especially during the songs.

[39] The film Geethanjali which had Nagarjuna and Girija Shettar in the lead, told the story of an ill-fated couple, both of whom are suffering from terminal diseases.

[40] Mani maintained a momentum of making emotional stories of under-served people through the film Anjali in 1990, which starred Baby Shamili as the central character.

[43] The film was loosely based on Mahabharata, dealt with the friendship between Karna and Duryodhana portrayed by Rajinikanth and Mammmooty respectively.

[47] It became highly popular, gaining an iconic status in Indian cinema and was dubbed into other languages and met similar success in other regions.

Scripted by Ram Gopal Varma,[49] the film was a fun filled caper,[50] which was a departure from Mani's previous style and fared moderately well at the box office.

[56] Mani produced his wife's directorial debut film, Indira,[57] and then directed the critically successful Iruvar with Mohanlal, Aishwarya Rai, Tabu and Prakash Raj in the lead.

[58] In 1998 came the third part of his "terrorism trilogy", named Dil Se.. and starring Shahrukh Khan and Manisha Koirala, with the latter fabricating the second collaboration.

[60][61] Unlike his previous two projects, Dil Se.. opened with little note among film critics and performed poorly in the domestic market,[62] despite being a success overseas.

[77] In 2004, he made Aayutha Ezhuthu, which tells the story of how one incident sends the lives of three youths on a collision course and received positive reviews.

Ajay Devgn, Abhishek Bachchan, and Vivek Oberoi replaced Surya Sivakumar, R. Madhavan, and Siddharth, respectively in the Hindi version.

[59] In 2007, Mani made Guru, a biographical film based on the life of Dhirubhai Ambani, a business magnate from India.

[86] The film is loosely based on the Hindu epic Ramayana; its narrative occurs over 14 days when a revolutionist named Veera, who lives in a forest, kidnaps a policeman's wife to avenge his sister's death.

[90] His next film, romantic drama O Kadhal Kanmani starring Dulquer Salmaan and Nithya Menen as the lead pair, was released in April 2015.

The film depicted the life of a young couple in a live-in relationship in Mumbai, and was said to be a "reflection of the modern mindset of urban India", dealing with issues such as marriage and traditional values.

After Kattru Veliyadai, Ratnam's next film was the crime thriller Chekka Chivantha Vaanam, starring Arvind Swami, Silambarasan, Arun Vijay and Vijay Sethupathi as the lead actors, while Jyothika, Aishwarya Rajesh, Aditi Rao Hydari and Dayana Erappa, Prakash Raj, Thiagarajan, and Mansoor Ali Khan rounded out the supporting cast.

The film has an ensemble cast consisting of Vikram, Karthi, Jayam Ravi, Jayaram, Rahman, Aishwarya Rai, Trisha, Aishwarya Lekshmi, R. Parthiban, Lal, Babu Antony, Ashwin Kakumanu, Prabhu, Sarathkumar, Sobhita Dhulipala, Vikram Prabhu and many more, play the prominent roles.

[100] He is greatly influenced by the film-making styles of Akira Kurosawa, Martin Scorsese, Krzysztof Kieślowski, Ingmar Bergman and Mahendran.

[51] Right from the beginning of his career, his works were noted for their technical expertise in areas such as cinematography, art direction, editing and background score.

For his debut film, he managed to handpick Balu Mahendra, Thotta Tharani, B. Lenin, and Ilaiyaraaja, leading craftsmen in their respective fields.

[24][114] In July 2015, he was honoured with the Sun Mark Lifetime Achievement Award at the Bagri Foundation London Indian Film Festival for his esteemed contribution to international cinema.