She is a veteran politician of the Bharatiya Janata Party and also served as the Speaker of the 16th Lok Sabha.

In 2014, She got elected to the Lok Sabha for the eighth time, one of three members of the Lok Sabha to do so. She represented the Indore constituency of Madhya Pradesh from 1989 to 2019.

She served as the Union Minister from 2002 to 2004, holding the portfolios for Human Resources, Communications and Petroleum.

She is the second woman after Smt. Meira Kumar to be elected as the Speaker of the Lok Sabha.

She has acknowledged the 18th century social reformer Ahilyabai Holkar as the inspirational figure throughout her life

She ran for the first time and won the Lok Sabha elections in 1989, against the former Chief Minister and senior a Congress leader. She has brought many projects for Indore from Railways, Aviation, Urban Development Ministry.

She is known for simplicity, honesty and clean politics. She has a clean track record and has always maintained distances from Special Interest Group. She is popularly known as Tai, among people of her constituency.

In February, Smt. Sumitra Mahajan was included in the LIMCA book of records for being first Indian woman to represent the same Lok Sabha constituency on the same party ticket for eight times in a row.