Mamata's tryst with politics began in the 1970s when she joined the Congress. In the 1984 general elections, she became one the youngest members in Parliament beating Communist leader Somnath Chatterjee's record.

She also became the general secretary of the All India Youth Congress. She lost her seat in 1989 but was re-elected in the 1991 general elections.

She retained the Kolkata South seat in the 1996, 1998, 1999, 2004 and 2009 general elections. In 1997, Mamata Banerjee split the Congress party in West Bengal and established the All India Trinamool Congress. In 1999, she joined the Bharatiya Janata Party-led National Democratic Alliance government as the railway minister.

In 2001, after parting ways with the BJP, she moved out of the Cabinet. She then joined hands with the Congress party for West Bengal's 2001 elections.

She returned to the Cabinet in January 2004, holding the Ministry of Coal and Mines portfolio till 2004.

The 54-year-old Mamata won from the Kolkata South constituency this time, in one of the best performances by an opposition party in West Bengal.