Mammootty was born and raised in Chempu near Vaikom in the Kottayam district of the state of Kerala, India in a middle class, Muslim family. He was the eldest son of the family. His father Ismail was a farmer and his mother Fatima was a housewife. His father shifted his family to Ernakulam on 1960s, his school life was at St. Albert s School and Government School Ernakulam. He did his pre-degree at Maharajas College, Kochi, and then graduated with a L.L.B. from Ernakulam Government Law College. He also practiced law for two years in Manjeri. He married Sulfath in 1980 and has a daughter, Surumi and a son, Dulquer Salmaan.

Mammootty’s debut was an uncredited appearance in the 1971 film Anubhavangal Paalichakal. His only scene in the film was being one among a running crowd along with the lead actor Sathyan. Mammootty then was a student at the Maharajas College. His second film was Kaalachakram, a 1973 Malayalam film. This was the first dialogued appearance of Mammootty, appearing only in one scene in the film. He acted under the screenname Sajin, but later dropped it.

His professional film career began in 1979, when he played his first lead role in Devalokam, directed by veteran M. T. Vasudevan Nair. However, this film was never completed. His next film was the 1980 film, Vilkkanundu Swapnangal, featured Mammootty, as an antagonist in a supporting role. Voice for Mammootty in this film was dubbed by Sreenivasan. Mammootty’s first full length character was in the 1980 film Mela as an antagonist. Mammootty began to establish himself as an actor and as a star through his film of the 1980s viz Sphodanam, Thrishna etc. In 1981, he got his first state award in the Best Supporting Actor category for his performance in Ahimsa. His performances in films like Aalkkoottathil Thaniye and Adiyozhukkukal, established him as an actor of substance. The role of a police officer in the investigative thriller Yavanika cemented his position as a hero in Malayalam cinema. The film was a big commercial success and Mammootty’s role got rave reviews for its style and dialogue delivery. This was the beginning of a trend whereby Mammootty would play the role of a tough cop in many action and investigative thrillers in the coming years. In a period of five years from 1982 to 1986 Mammootty acted in more than 150 films in the lead role. In 1986 alone, he acted in about 35 films in the lead role. The mid of 80s saw a period of tear busting stories in Malayalam film. Most of the films were tragedies. This period featured what later came to be referred to as the ‘Mammootty-Kutty-Petty’ films. These films had Mammootty as the protagonist, a husband and a father, with a 3–4 year old daughter, and employed in a top ranking post in a company. Mammootty made a comeback with New Delhi and Thaniyavarthanam, both released in 1987.

In 1988 Mammootty delivered one of the biggest hits in the history of Malayalam Cinema with his Oru CBI Diary Kurippu. Oru CBI Diary Kurippu went on to create box-office history in Kerala as well as in Tamil Nadu. Mammootty’s role as a CBI officer in this film got him critical acclaim. Following the success of the first CBI film Oru CBI Diary Kurippu, three more murder mystery sequels were produced with the same cast of characters: Jagratha (1989), Sethurama Iyer CBI (2004) and Nerariyan C.B.I (2005), with Mammootty as Sethurama Iyer, an intelligent but unassuming CBI officer. Mammootty touched the pinnacle of his career in Oru Vadakkan Veeragatha; the film was directed by T. Hariharan and penned by M.T.Vasudevan Nair. His depiction of a Chekavar of distinguished valor but vilified by circumstances won him the National Film Award for Best Actor.

The period 2001–2003 was of a big setback for Mammootty. The 2004 film, the third installment in the CBI series, Sethurama Iyer CBI marked his come back. In 2006, he did I. V. Sasi’s Balram vs. Tharadas, in which he reprised his roles Inspector Balram from the 1991 blockbuster Inspector Balram and Tharadas from the 1984 blockbuster Athirathram. It was I. V. Sasi’s 144th film, and a record 35th with Mammootty. Mammootty’s career graph raised spectacularly after the release of Rajamanikyam directed by debutant Anwar Rasheed. Released during Ramadan 2005, the movie broke all collection records and became the biggest hit of 2005. Rajamanikyam was also touted as the biggest hit of all time ever produced in the Malayalam cinema. His movie “Mayabazaar” holds the record for highest channel right collecting film in Malayalam Film Industry, by selling the channel right for 1.3 crore. The record breaks his own record of 1.1 crore for the film Annan Thambi.

Mammootty has acted in a few non-Malayalam movies and these include some Tamil, Telugu, Hindi, Kannada and English films. In 1989, he made his Tamil debut in Maunam Sammatham. He has acted in Tamil films for directors including K. Balachander (Azhagan), Mani Ratnam (Thalapathy), and Rajiv Menon (Kandukondain Kandukondain). Kilippechu Kekkavaa (1993), directed by Fazil, had Mammootty as a romantic hero. He played the role of Anantha Sharma in K. Vishwanath’s Telugu film Swathi Kiranam (1992). He acted in the Kannada film Shikari in 2011. He made his debut into Hindi films through Thriyathri which was released in 1989, though his first film as a hero was Dhartiputra. He starred in the biographical film Dr. Baba Saheb Ambedkar directed by Jabbar Patel which was in the English language. He also appeared in Sau Jhooth Ek Sach (2004).

Mammootty is involved in more than half a dozen philanthropic projects aimed at helping needy people. Mammootty is the patron of the Pain and Palliative Care Society, a charitable organization in Kerala formed with the aim of improving the quality of life among patients with advanced cancer. He has been the fuel and the engine of the Pain and Palliative Care Center situated in Kozhikode, India. Mammootty has now put forth a novel project to provide the pain and palliative care to those suffering from cancer throughout Kerala. Mammootty is the ambassador of Jeevan Jothi, a social work project aimed at providing aid to people seeking treatment for any ophthalmic diseases, cardiac diseases, orthopedic diseases, liver diseases, renal dysfunction, Hemophilia diseases, or ENT disorders. Mammootty is the goodwill ambassador of a charity project “Street India Movement”, which is aimed at the eradication of child begging and child labor. Kazhcha is a venture to extend free eye care and treatment organized by Mammootty Fans Welfare Association and Mammootty Times, in association with Little Flower Hospital and Research Centre and the Eye Bank Association of Kerala. Akshaya, the information technology dissemination project of the Government of Kerala, has Mammootty as its Goodwill Ambassador. He formally took over the role on 26 February 2006 at a video networked programme which was linked to all the district headquarters of the state. Mammootty spearheaded the campaign by appearing in print and visual media advertisements and other publicity materials that sent the message of the Akshaya project to the grassroots. Mammootty is a patron of “Share International Foundation”, a charity organization working towards removing the inequalities in society. The foundation has done many notable humanitarian works including the recent “Hridaya Sparsham project of the Care”, to mobilize help for the heart surgery of children. Mammootty’s plea over the social networking sites evoked aid worth about 1 crore within a day.

As of 2010, Mammootty is the Chairman of Malayalam Communications, which runs some Malayalam TV channels such as Kairali TV, People TV and Channel We. He owned a production company during the 1980s, Casino, along with Mohanlal, I.V. Sasi, Seema and Century Kochumon. The production house produced commercially successful films such as Nadodikkattu, Gandhi Nagar 2nd Street, Adiyozhukkukal and Karimpin Poovinakkare. He formed a television production company, Megabytes, which produced television serials, the first being Jwalayay in the late 1990s, which was also his first project as a producer. He also owns a distribution company named Mammootty Technotainment. The company distributed his Tamil film Karmegham in Kerala.

Mammootty was appointed as the Global Brand ambassador of the Kerala-based South Indian Bank on 16 October 2006. He was also featured as the brand ambassador for Kerala Volleyball League. Mammootty wrote his first book Kazhchapadu Mammootty owns the distribution company Playhouse Entertainments.