Born in Alor Star, the capital of the northern state of Kedah, Mahathir said in his autobiography that he had Indian ancestry (from his father), with its origins tracing back to Kerala in India, while his mother was a Kedah-born Malay. Mahathir, however, considers himself to be a "full Malay", in line with Article 160 of the Constitution. Under Article 153 of the Constitution, Malays are granted particular rights not available to other citizens.
Mahathir first attended a Malay vernacular school before continuing his education at the Sultan Abdul Hamid College in Alor Star. Mahathir then attended the King Edward VII Medical College in Singapore, where he edited a medical student magazine called The Cauldron; he also contributed to the Straits Times newspaper anonymously under the nickname "Che Det". Mahathir was also President of the Muslim Society in the college  In 1953, Mahathir entered the then Malayan government service as a medical officer upon graduation. He married Dr Siti Hasmah Mohd Ali — a former classmate in college — on August 5, 1956, and left the government service in 1957 to set up his own practice in Alor Star.
Active in politics since 1945, beginning with his involvement in the Anti-Malayan Union Campaign, Mahathir joined the United Malay National Organization (UMNO) upon its inception in 1946. As State Party Chairman, and Chairman of the Political Committee, he inadvertently angered some quarters with his proposal that the selection of candidates be based on certain qualifications for the 1959 general election. Hurt by accusations that he was scheming to put up candidates who were strongly allied to him, Mahathir refused to take part in the national election that year.
In the third general election of 1964, Mahathir was elected Member of Parliament for Kota Setar Selatan , defeating the Pan-Malaysian Islamic Party's (PAS) candidate with a 60.2% majority. He lost the seat in the following general election in 1969 by a mere 989 votes to PAS's candidate, Haji Yusoff Rawa , after he categorically declared that he did not need Chinese votes to win. (Ironically, Mahathir won the 1999 general elections mainly due to Chinese votes, when the Malay grounds were split over his quarrels with his deputy Anwar Ibrahim.)
Following the racial riots of May 13, 1969, Mahathir was sacked from the UMNO Supreme Council on 12 July, following his widespread distribution to the public of his letter to Tunku Abdul Rahman, the then Prime Minister. In his letter, he had criticised the manner in which the Tunku had handled the country's administration. Mahathir was subsequently relieved of his party membership on 26 September.
While in the political wilderness, Mahathir wrote his book, "The Malay Dilemma" , in which he sought to explain the causes of the May 13, 1969 riots in Kuala Lumpur and the reasons for the Malays' lack of economic progress within their own country. He then proposed a politico-economic solution in the form of "constructive protection", worked out after careful consideration of the effects of heredity and environmental factors on the Malay race. The book, published in 1970, was promptly banned by the Tunku Abdul Rahman government. However, some of the proposals in this book had been used by Tun Abdul Razak, the second Prime Minister, in his "New Economic Policy" that was principally geared towards affirmative action economic programs to address the nation's economic disparity between the Malays and the non-Malays. The ban on his book was eventually lifted after Mahathir became Prime Minister in 1981.
Mahathir rejoined UMNO on 7 March 1972, and was appointed as Senator in 1973. He relinquished the senatorship post in 1974 in order to contest in the general elections where he was returned unopposed in the constituency of Kubang Pasu, and was appointed as the Minister of Education. In 1975, he became one of the three vice-presidents of UMNO, after winning the seat by 47 votes. Tun Hussein Onn appointed Mahathir as Deputy Prime Minister on 15 September 1978, and in a cabinet reshuffle, appointed him concurrently as the Minister of Trade and Industry.
Mahathir became the Prime Minister of Malaysia on 10 July, 1981 when Tun Hussein Onn stepped down due to health reasons. He resigned as Prime Minister on October 31, 2003 after 22 years in office, making him one of Asia's longest-serving political leaders. Upon his retirement on 31 Oct 2003, Mahathir was awarded a "Tun"-ship, Malaysia's highest honour.
- 1925: Born in Alor Star, Kedah on July 10 (often documented as December 20).
- 1945: Joined the Anti-Malayan Union Campaign.
- 1946: Joined the United Malays National Organization (UMNO) as a member upon its inception.
- 1953: Graduated as a physician from King Edward VII Medical College, Singapore (subsequently became the medical faculty of the University of Malaya;
- Joined the Malaysian government service as a medical officer upon graduation.
- 1956: Married Dr Siti Hasmah Mohd Ali on August 5.
- 1957: Left the government medical service to set up his own practice in Alor Star.
- 1957: His first child Marina Mahathir was born in June, she is Mahathir bin Mohamad's eldest daughter.
- 1958: Mirzan was born in November, it is his second child and first son.
- 1961: Mokhzani was born in January, it is his third child and second son.
- 1964: Elected Member of Parliament for Kota Setar South on an Alliance Party ticket, defeating the Pan-Malaysian Islamic Party'(PAS) candidate with 60.2% of the votes polled.
- 1964: Mukhriz was born in November, it is his youngest child and third son.
- 1965: Elected as a member of the UMNO Supreme Council.
- 1968: Appointed as Chairman of the first Higher Education Council.
- 1969: Lost his parliamentary constituency of Kota Setar South to PAS's candidate, Haji Yusoff Rawa, by 989 votes;
- Sacked from the UMNO Supreme Council on July 12, following the widespread distribution to the public of Mahathir's letter to Tunku Abdul Rahman, then Prime Minister and President of UMNO;
- Relieved of his party membership on September 26.
- 1970: Published "The Malay Dilemma" that was soon banned.
- 1972: Rejoined UMNO on March 7.
- 1973: Appointed as a Senator.
- 1974: Appointed Chairman of the National University Council;
- Relinquished the post of Senator in order to contest in the 1974 General Elections where he was returned unopposed;
- Appointed as the Minister of Education on September 5.
- 1975: Became one of the three vice-presidents of UMNO, after winning the seat by 47 votes.
- 1976: Elected as Deputy President of UMNO on March 5.
- 1978: Appointed Deputy Prime Minister by the then Prime Minister, Tun Hussein Onn on September 15;
- Relinquished the Education portfolio to become Minister of Trade and Industry (June 1, 1978 – July 1981;
- 1981: Elected as UMNO President on June 26;
- Appointed as Prime Minister of Malaysia on July 10, when Tun Hussein Onn stepped down for health reasons;
- Concurrently took charge of the Ministry of Defence (July 18, 1981 – May 6, 1986);
- Launched the slogans for a "Clean, Efficient and Trustworthy Government"; "Leadership Through Example", the "Look East Policy"; "Permeation of Islamic Values", and "Buy British Last";
- Moved the clock by half an hour in Peninsular Malaysia to bring it in line with East Malaysia;
- Made a public apology to Tunku Abdul Rahman;
- Engineered the dawn raid in Malaysia’s takeover of Guthrie Corporation by Perbadanan Nasional Berhad (PNB) in the London Stock Exchange on September 7 to return ownership of some 200,000 acres (800 km²) of agricultural land to the people.
- 1983: Removed royal veto, such that a bill could becom law on approval by parliament;
- Initiated Perusahaan Otomobil Nasional, a national car project.
- 1986: Musa Hitam resigned as Deputy Prime Minister on February 27;
- Appointed Ghafar Baba as Deputy Prime Minister;
- Concurrently took charge of the Ministry of Home Affairs on May 7;
- A major diplomatic row erupted with neighbouring Singapore when Chaim Herzog, the President of Israel, paid a state visit.
- 1987: Narrowly warded off a challenge by Tengku Razaleigh for the post of UMNO president on April 24.
- 1988: Engineered the dismissal of the Lord President of the Supreme Court, Salleh Abas, and three other supreme court justices who tried to block the misconduct hearings, when the future of the ruling party UMNO was about to be decided in the Supreme Court (it had previously been deregistered as an illegal society in the High Court);
- 1990: Took over the Ministry of Home Affairs (October 1990 – January 1999);
- 1993: Appointed Anwar Ibrahim as Deputy Prime Minister;
- Limited the legal immunity of the monarchy, after the Douglas Gomez incident;
- Relationships between Mahathir and Australia's leaders reached a low point when Paul Keating described Mahathir as "recalcitrant" for not attending the APEC summit. [It is thought that Keating's remark was a linguistic gaffe, and that he actually meant "intransigent".]
- 1997: Introduced the currency peg to resolve the 1997 Asian financial crisis on September 1.
- 1998: Sacked his deputy, Anwar Ibrahim;
- Relations with the United States took a turn for the worse, when US Vice President Al Gore made a derogatory statement at the APEC conference hosted by Malaysia.
- Brought trumped-up sodomy and abuse of power charges against Anwar Ibrahim following a disagreement on certain political issues;
- Appointed Abdullah Ahmad Badawi as Deputy Prime Minister;
- Official opening of the Kuala Lumpur International Airport (KLIA) in Sepang, built at a cost of USD$3.5 billion;
- Completion of the 88-storey Petronas Twin Towers, the tallest twin towers in the world;
- Named as "Asia's Newsmaker of 1998" by TIME Magazine.
- 1999: Took over the Ministry of Finance on January 8;
- Official opening of Cyberjaya, a township that is a key part of Malaysia's "Multimedia Super Corridor".
- 2001: Took over the Ministry of Special Functions on June 5.
- 2002: Announced that Mathematics and Science subjects will be taught in English, rather than in Malay with effect from 2003;
- Announced his resignation to the UMNO General Assembly, but was persuaded to stay on for a further eighteen months.
- 2003: Retired as Prime Minister of Malaysia on October 31, after 22 years in office, making him one of Asia's longest-serving political leaders;
- Awarded the Tun-ship, Malaysia's highest honour.