Jyoti Basu was born on 8 July 1914 as Jyotirindra Basu at 43/1 Harrison Road (now Mahatma Gandhi Road) Calcutta into an upper middle-class Bengali family in West Bengal, India. His father, Nishikanta Basu, was a doctor from the village of Barudi in Narayanganj District, East Bengal (now in Bangladesh), while his mother Hemalata Basu was a housewife. Basu's schooling started at Loreto School at Dharmatala, Calcutta (now Kolkata), in 1920. It was there where his father shortened his name and he became Jyoti Basu. However, he was moved to St. Xavier's School in 1925. Basu completed his undergraduate education and received the honours in English from the Presidency College of the University of Calcutta.

After completing his undergraduate studies in 1935, Basu set for England for higher studies of Law. It is said that Basu attended lectures by Harold Laski at the London School of Economics in late 1930. It was in England that Basu was introduced to the activities of politics through the Communist Party of Great Britain. There he was inspired by noted Communist philosopher and prolific writer Rajani Palme Dutt. In 1940 he completed his studies and qualified as a Barrister at the Middle Temple. In the same year he returned to India. In 1944 Basu became involved in trade union activities when CPI delegated him to work amongst the railway labourers. When B.N. Railway Workers Union and B.D. Rail Road Workers Union merged, Basu became the general secretary of the union.

Basu's first track in politics was his effort to organize the Indian students studying in the United Kingdom, mostly for the cause of Indian independence. Basu subsequently joined India League and London Majlis, both organizations being communities of overseas Indian students. Basu was later elected the General Secretary of London Majlish. Basu was given the responsibility of arranging a meeting with Jawaharlal Nehru during Nehru's visit to London in 1938. The same was done after Subhas Chandra Bose went to England. As a member of London Majlis, Basu introduced the visiting Indian political figures to the leaders of the Labour Party.

Basu was introduced to the Communist Party of Great Britain by another communist leader and Basu's friend in England, Bhupesh Gupta. It is said that Basu showed interest to join CPGB but the then Secretary General Harry Pollitt suggested that he should not do so, possibly because CPGB was then banned in India and Pollitt speculated Basu could have difficulties in returning to India as a member of CPGB. However Basu returned to India in 1940 and immediately contacted the Party leaders. Though he enrolled himself as a barrister in Calcutta High Court, he never practised simply because he was determined to become a wholetimer of the Party. Basu became the secretary of Friends of Soviet Union and Anti-Fascist Writers' Association in Kolkata. As a member of the Party, his initial task was to maintain liaison with underground Party leaders. He was entrusted with responsibilities on the trade union front from 1944. In that year, Bengal Assam Railroad Workers' Union was formed and Basu became its first secretary. Basu was elected to Bengal Provincial Assembly in 1946 from the Railway Workers constituency. Ratanlal Bramhan and Rupnarayan Roy were the other two Communists who were elected. From that day on, Basu became one of the most popular and influential legislators for decades to come.

Basu played a very active role in the stormy days of 1946–47 when Bengal witnessed the Tebhaga movement, workers strikes and even communal riots.

Jyoti Basu was the secretary of the West Bengal Provincial Committee of the Party from 1953 to January 1961. He was elected to the Central Committee of the Party in 1951. He was a member of the Politburo from 1964 onwards. He was elected as a special invitee to PB in the 19th Congress of the Party in 2008.

After the country gained independence, he was elected to the assembly from Baranagar in 1952. He was elected to the West Bengal Legislative Assembly in 1952, 1957, 1962, 1967, 1969, 1971, 1977, 1982, 1987, 1991 and 1996. Though an elected member, Basu was arrested several times during the 1950s and 60s and for certain periods he went underground to evade arrest by the police.

In 1962, Jyoti Basu was one amongst 32 members of the National Council who walked out of the meeting. When the CPI (M) was formed in 1964 as a result of the ideological struggle within the Communist movement, Basu became a member of the Politburo. He was, in fact, the last surviving member of the "Navaratnas", the nine members of the first Politburo. The leftist section, to which the 32 National Council members belonged, organized a convention in Tenali, Andhra Pradesh, July 7 to 11. It was here where the radical sections of the party further showed their pro-Chinese stand. The Tenali convention was marked by the display of a large portrait of the Chinese Communist leader Mao Zedong.

Basu was elected to the Bengal Legislative Assembly in 1946, contesting the Railway constituency. He served as the Leader of Opposition for a long time when Dr. Bidhan Chandra Roy was the Chief Minister of West Bengal. Basu's admirable eloquence both as an M.L.A and the Leader of Opposition drew the attention of Dr. B.C. Roy and he had a strong affection for this young leader though his stand was completely contrary to the policies of the then State Government run by Dr. Roy. Jyoti Basu led several agitations against the State Government and earned enviable popularity as a politician particularly among the students and youth. Besides organising the movements of the Railway Labourers, he led a movement by the teachers demanding a hike in salary. When the Communist Party of India split in 1964, Basu became one of the first nine members of the Politburo of the newly formed Communist Party of India (Marxist). In 1967 and 1969, Basu became Deputy Chief Minister of West Bengal in the United Front governments. In 1967, after the defeat of the Congress Government, Jyoti Basu was sworn-in as the Deputy Chief Minister under the Chief Ministership of Ajoy Mukherjee. In 1970, he narrowly escaped an assassination attempt at the Patna railway station by the Anand Margis. Though CPI (M) became the single largest party in the assembly elections in 1971, the party was refused the chance to form a ministry and Presidents' Rule was imposed in West Bengal. Through the 1972 elections the Congress returned to power in West Bengal. Jyoti Basu as a result lost the elections from the Baranagar Assembly Constituency. Jyoti Basu was forced to boycott the elections. Basu famously declared the new assembly as "assembly of the frauds" and CPI (M) boycotted the assembly for the next five years. Jyoti Basu belonged to the leadership of the CPI (M) which steered the Party through the difficult days of semi-fascist terror in West Bengal in the early seventies.

After the sweeping victory of the Left Front in 1977, Jyoti Basu became the Chief Minister of the Left Front government, a position he held continuously for more than 23 years, a record in the country (From June 21, 1977, to November 6, 2000, Basu served as the Chief Minister of West Bengal for the Left Front government). Under his leadership, the Left Front government embarked on land reforms on a scale unprecedented in the country; it instituted a panchayati raj system which was radical for its times, which gave the poor peasants and small farmers a say in running the panchayati institutions. West Bengal became an oasis of communal harmony and secular values under his leadership. One has to recall how as Chief Minister he dealt with the situation after the assassination of Indira Gandhi in 1984 when violence against Sikhs broke out in various parts of the country, but nothing was allowed to happen in West Bengal. Similarly he dealt firmly with efforts to instigate trouble after the demolition of the Babri Masjid in 1992. In 1996 Jyoti Basu seemed all set to be the consensus leader of the United Front for the post of Prime Minister of India. However, the CPI (M) Politburo decided not to participate in the government, a decision that Jyoti Basu later termed a historic blunder. H.D. Deve Gowda from the Janata Dal instead became Prime Minister. Basu resigned from the Chief Ministership of West Bengal in 2000 for health reasons, and was succeeded by fellow CPI (M) politician Buddhadeb Bhattacharya. As of 2010, Basu holds the record for being the longest-serving Chief Minister in Indian political history.

The 18th congress of CPI(M), held in Delhi in 2005, re-elected Basu to its Politburo, although he had asked to be allowed to retire from it. On September 13, 2006, Basu entreated the CPI (M) to allow his retirement due to his age, but was turned down. General Secretary Prakash Karat said that the party wanted Basu to continue until its 2008 congress, at which point it would reconsider. At the 19th congress in early April 2008, Basu was not included on the Politburo, although he remained a member of the Central Committee and was designated as Special Invitee to the Politburo. Jyoti Basu became a symbol for the Left, democratic and secular forces in the country. In West Bengal, the people adored him and respected him for his championing of their cause. He became the role model for all Communists and progressives on how to work in parliamentary institutions and serve the people. During this seven decades of work in the Communist party, he spent three and a half years in prison and two years underground. Jyoti Basu was a Marxist who never wavered in his convictions. After the fall of the Soviet Union and the setbacks to socialism, he provided the leadership along with his colleagues in the Politburo to make a reappraisal of the experience of building socialism and to pinpoint the errors and to correct wrong notions and understandings while remaining true to Marxism-Leninism. He was a Marxist who was not dogmatic and continued to learn from his vast experience in charting out the course for the Party. He emerged as the pre-eminent and most popular leader of the Party, but he always worked as a disciplined member of the Party, setting an example for all. In his long career in the Party, he undertook various responsibilities including being the first editor of People's Democracy. He had a lifelong association with the trade union movement and was the Vice-President of the Centre of Indian Trade Unions since its inception in 1970.

Some commentators feel Basu was more of a democratic socialist than a traditional Communist. "He made Communism look respectable," according to Sabyasachi Basu Roy Choudhuri, a Calcutta-based political analyst. Sumon K Chakrabarti, the national affairs correspondent for CNN-IBN, said in his blog that during Basu's tenure as the Chief Minister of West Bengal, the state saw continuous industrial decline. An obituary of Basu on NDTV noted that he had been criticised for economic policies based on his communist ideology, which led to economic stagnation in the state and emigration of workers; removal of English from primary schools and initial support of trade unions against the use of computers, which adversely impacted employment; and, the charge that his party members engaged in corruption and rigging of elections, though such allegations were not proven.

On 1 January 2010, Basu was admitted to AMRI hospital, Saltlake Bidhannagar, Kolkata, after he was diagnosed with pneumonia. On 16 January 2010, his health condition became extremely critical and he was suffering from multiple organ failure. Seventeen days after being taken ill, he died on 17 January 2010 at 11:47 am IST.

Basu had pledged to donate his body and eyes for medical research on 4 April 2003 at a function organised by Ganadarpan and Susrut Eye Foundation in Kolkata and not to be burned at a crematorium. His eyes are donated to Susrut Eye Foundation. Basu's body was kept at 'Peace Haven' for those who wanted to pay their respects. His body was handed over to SSKM Hospital, Kolkata, for research on 19 January 2010 around 16:50 pm IST after a guard of honour at the nearby Moharkunja park (formerly, citizens' park). The hospital authority is currently considering preserving his brain.