In 1964, Mahathir, a physician by profession, entered the Malaysian parliament as a member of the dominant United Malays National Organization (UMNO) party. He held several ministerial posts in the 1970s, including deputy prime minister beginning in 1976.
During his term in office, Mahathir forcefully guided Malaysia's development as a regional high-tech manufacturing, financial, and telecommunications hub through his economic policies mediated by corporate nationalism, which were flagged as the National Economic Policy, and remained in effect almost to the end of his terms of office.
His greatest success has been to maintain peace between the various races in Malaysia, by creating a Malay middle class, independent of the traditionally dominant Chinese minority.
During the racially turbulent 1960s and 1970s, Mahathir had been known as a Malay ultra (famously labelled as such by the Singapore Prime Minister Lee Kuan Yew) or extremist, and was expelled by his party for the publication of The Malay Dilemma in 1970. The title dogged him through his career and beyond. It became a coded reference to Malaysia's preferential race policy and its impact on the nation's delicate race dynamics and economy. Unlike affirmative action in the U.S., Malaysia's far more aggressive and pervasive racial policy has been remarkably successful in creating a sizable and stable Bumiputra ('indigenous group') middle class. There has been a significant cost, however, which Malaysians were reluctant to address as long as Mahathir was in control: the consequent distortion of freemarket dynamics is said to have fostered favoritism and inefficiency. In private, Malaysians dubbed the favored group the 'UMNO-putras' The extent to which cronyism is fostered is debated, but the perception of it led to the depreciation of the ringgit during the 1997 Asian financial crisis, and eventually to Mahathir's loosened grip on the sources of power. Nonetheless, largely due to the economic development of the country, which by and large has benefited all races, he leaves behind a peaceful, prosperous, and self-confident Malaysia.
During the 1997 Asian financial crisis, he was strongly criticized by the international financial community for contravening IMF policies by keeping interest rates down and braking the flow of foreign capital, but it meant that Malaysia's downturn was shorter and shallower than those of the other countries affected. Mahathir blamed currency speculators for the crisis, foremost among them George Soros. Critics said his accusations were "tinged with anti-semitism."
With a twenty-two year grip on power, Mahathir is also seen as a political "strongman", and has been criticised for his authoritarian policies and use of state power to suppress opponents via the media, the judiciary and law enforcement agencies. In 1983 and 1991, he took on the federal and state monarchies, removing the royal veto and royal immunity from prosecution.
In 1988, 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), he engineered the dismissal of the Lord President of the Supreme Court, Tun Salleh Abas, and three other supreme court justices who tried to block the misconduct hearings.
In 1997, skeptical attention around the globe was focused on Malaysia when the government brought sodomy and abuse of power charges against the former finance minister and deputy prime minister, Anwar Ibrahim. Anwar and his supporters tried to turn corruption and nepotism into major political issues, with Mahathir and his associates the unstated target, and this unleashed the wrath of the government.
Many observers saw the engineering of Anwar's dismissal as the result of the triumph of the secular corportate nationalist old guard over the younger "green" or Islamist faction within UMNO, created after the popular Islamic youth leader Anwar had been brought into the government by Mahathir.
In separate trials, Anwar was sentenced to six years in prison for corruption and nine years prison for sodomy, to be served concurrently. Both Amnesty International and Human Rights Watch expressed serious doubts about the fairness of the trials. 
The Anwar crisis sparked unprecedented massive protests by Malaysians, of all ethnic groups, and many of Anwar's supporters from UMNO regrouped around the intellectual-Muslim "Parti Keadilan" (Justice Party).
Mahathir has been a outspoken proponent of 'Asian values' of authoritarian state-led capitalism, as an alternative to American individualism and laissez-faire capitalism. In general, Mahathir is perceived as a moderate Muslim, but he is not above playing the fundamentalist card for political advantage. When the more fundamentalist Parti Islam seMalaysia (Islamic Party of Malaysia, PAS) started to gain power (it now controls the two northern states if Terengganu and Kelantan, where it has introduced some Islamic sharia legislation) and made strong inroads into Mahathir's homestate of Kedah, Mahathir tried to bolster his party's position by declaring that Malaysia is an Islamic state, in spite of the country's largely secular constitution.
In 2002, a tearful Mahathir announced his resignation to a surprised UMNO General Assembly. He was persuaded to stay on for a further eighteen months, in a carefully planned handover that ended in October 2003. On his retirement he was granted Malaysia's highest honour, which entitles him to the title Tun.
Shortly before leaving office, Mahathir sparked off a fierce controversy when he called on Muslim leaders at the 57-member Organization of the Islamic Conference (OIC) summit to "fight back against their Jewish oppressors" who "ruled the world by proxy".  His comments were widely criticized in the West, but the issue was ignored in Asia. Mahathir later defended his remarks, saying "I am not anti-Semitic ... I am against those Jews who kill Muslims and the Jews who support the killers of Muslims." He tagged the West as "anti-Muslim", for double standards by "protecting Jews while allowing others to insult Islam." 
This last controversy was by no means the first blowup in the relationship between Western countries and Mahathir's Malaysia. Mahathir's personal relationship with the West has been turbulent a times. While his public statements about the US have often caused controversy, his image in Australia (the closest country in the Anglosphere to Malaysia, and the one whose foreign policy is most concentrated on the region), and his relationship with Australia's political leaders, has been particularly rocky. Mahathir regularly took offense at portrayals of Malaysia in the Australian media, calling on the government to intervene in this (an action that would politically unthinkable in Australia). Relationships between Mahathir and Australia's leaders reached a low point in 1993 when Paul Keating described Mahathir as "recalcitrant" for not attending the APEC summit. The Malaysian government threatened trade sanctions. Mahathir, along with other Malaysian politicians (and many other Asian leaders) also heavily criticised Keating's successor John Howard for allegedly encouraging Pauline Hanson, whose views were widely perceived in Asia as racist and harking back to the earlier White Australia policy. Mahathir's government is also widely perceived as being being efforts to exclude Australia from South East Asian intergovernmental agreements, such as ASEAN.
Mahathir is the author of the following books:
- The Malay Dilemma (1970)
- The Pacific Rim in the 21st Century (1995)
- The Challenges of Turmoil (1998)
- A New Deal for Asia (1999)
- Islam & The Muslim Ummah (2001)
- Globalisation and the New Realities (2002)
- Reflections on Asia (2002) ISBN 967978813X