Sushma was born in a middle-class family of Hardev Sharma and Shrimati Laxmi Devi in the Haryana city of Ambala on 14 February 1953. Her father was a prominent Rashtriya Swayamsevak Sangh member. Her parents hailed from Dharampura area of Lahore, Pakistan.
She was elected from Vidisha Lok Sabha constituency in Madhya Pradesh in 2014.
She was educated at Sanatan Dharma College in Ambala Cantonment and earned a bachelor's degree with majors in Sanskrit and Political Science. She studied law at Punjab University, Chandigarh. A state-level competition held by the Language Department of Haryana saw her winning the best Hindi Speaker award for three consecutive years.
In 1973, Swaraj started practice as an advocate in the Supreme Court of India. In 1975 she married lawyer and politician Swaraj Kaushal, who served a term (1990–93) as governor of Mizoram state.
She attended college in Haryana, completed a law degree at Panjab University in Chandigarh, and in 1973 registered as an advocate in the Supreme Court of India. While a student, she was politically active notably as the leader of a pro-Hindu organization associated with the RSS that was strongly opposed to the government of then-prime minister Indira Gandhi.
In 1984 she joined the BJP (which had been established by members from Janata in 1980) and was appointed the secretary of the party. She advanced in the party ranks to become its general secretary.
Swaraj failed three times (1980, 1984, and 1989) in her bids to win a seat in the Lok Sabha, losing each time to a candidate from the Indian National Congress (Congress Party). In 1990, however, she was elected to the Rajya Sabha (upper house of parliament). She successfully contested a seat in the Lok Sabha six years later and also briefly was a cabinet minister (Information and Broadcasting) in the 13-day BJP-led government of Atal Bihari Vajpayee (May–June 1996).
In 1998 she was reelected to the Lok Sabha and was briefly in charge of the same ministry (March–October) before resigning her seat to become the chief minister of Delhi (the first woman to hold that office), a position she held for less than two months (from mid-October to early December). After the BJP lost the 1998 Delhi assembly elections, Swaraj decided to return to national-level politics.
Swaraj had begun her political career with Akhil Bharatiya Vidyarthi Parishad in the 1970s. Her husband, Swaraj Kaushal, was closely associated with the socialist leader George Fernandes and Sushma Swaraj became a part of George Fernandes's legal defence team in 1975. She actively participated in Jayaprakash Narayan's Total Revolution Movement. After the Emergency, she joined the Bharatiya Janata Party. Later, she became a national leader of the BJP.