In 1977, he was elected as a Legislative Assembly Member for the first time. His constituency then was Cossipore. It was the first time that the CPI(M)-led Left Front came to power in West Bengal. He was given charge of the ministry of information and culture; it was his favorite position and during his tenure he contributed to Bengali theatre, movies and music.
After losing the 1982 assembly election from Cossipore, he changed his constituency to Jadavpur in 1987. The move was successful; he won comfortably and regained his post as information then Chief Minister of West Bengal), or the CPI(M), Bhattacharya resigned from the ministry.
Bhattacharya is also known to be a passionate cricket fan. An avid traveller, he has toured extensively in China, the erstwhile Soviet Union, Cuba, Vietnam, Great Britain, France and Singapore. Bhattacharyya and his wife Meera have a daughter, Suchetana who is an environment and wildlife activist.
In 1996, the CPI-M won the West Bengal assembly elections for the fifth consecutive time. Bhattacharya was once again appointed information and culture minister, but with additional authority over the home ministry. Basu continued looking after home.
Not only did the two leaders (Jyoti Basu & Bhattacharya) become closer during this period, Bhattacharya also matured as a politician. He is considered to be one of the few leaders who is both moderate and efficient and can balance both the hardliners and liberals in the party. Which was why, after 1996, he was always considered a viable alternative to Basu.
This eventually led to his being promoted the Chief Minister, when Basu finally decided to step down in 2000, ahead of the State Assembly elections due in May 2001. Though Basu was ill and aged, his government was fast losing popularity. There were unsubstantiated media stories about corruption involving Basu's son, and the state economy was generally losing steam. There was an investment flight away from the state, increased joblessness in urban areas, a serious crunch in technical and medical education facilities and a near-breakdown of health services at the time. Bhattacharya was made the Chief Minister with the objective of making the administration look cleaner (he is seen as 'uncorruptible' to this day even by his critics)and more efficient. His clean image was primarily responsible for winning a record 6th term for the Left Front government in West Bengal in May 2001, though with a much reduced majority.
After becoming the chief minister Bhattacharya has liberalised Bengal's economy significantly. He has attracted a lot of foreign investment in Bengal. Many new industries and IT related services have emerged under his leadership. He is generally seen as a Communist leader who is open to reforms. However, his opponents have criticized him for taking farmlands to build industries. Bhattacharya said in return, that these farmlands were not so productive and they will provide better jobs to many poor people. Some communists have also criticized Bhattacharya for pursuing economic reforms. Recently Bhattacharya said that he does not want to unionize the IT industry. Labour unions of Bengal have criticized this decision saying that this will lead to the exploitation of IT workers.
His biggest asset proved to be his clean image, which helped him lead the Left Front to a 7th consecutive term in 2006 Assembly Elections. He personally won from Jadavpur constituency with 127,837 votes. His victory margin went up from 29,281 in 2001 to 58,130 in 2006. His coalition improved its tally from 199 seats (out of 300) to 235 and reduced the other opposition parties to insignificance.
Buddhadev Bhattacharya's Government came under heavy criticism for police action against demonstrators in Nandigram. He was criticized not only by opposition parties (such as the Trinamool Congress) and other Left Front coalition allies like CPI, RSP and Forward Bloc, who threatened to back out from the ministry on this issue, but also by his mentor and the state's former chief minister, Jyoti Basu. On March 15, 2007 Basu criticized Bhattacharya for failing to restrain the police in Nandigram. Bhattacharya has expressed regret for the shootings, but claimed that his intention in permitting police action was because Nandigram was an "area where there had been no rule of law and no presence of an administration for not one, two or 10 days but for two-and-a-half months, and many hundreed of villagers were thrown out of nandigram by trinmool partisans, more these villagers taking shelter in a state relief camp outside nandigram, also their land in villages were also captured by the goons. The CPI(M) has declared that they are totally behind Bhattacharya and have drawn up "plans" to placate his critics in the Left Front.