The Janata Dal (Secular) traces its roots back to the Janata Party organised by Jayaprakash Narayan that united all anti-Indira Gandhi parties under one banner for the 1977 Lok Sabha elections.
The Janata Dal was formed in Bangalore with the merger of the Janata Party with smaller parties in 1988. In 1996, the party reached its pinnacle when H D Deve Gowda became Prime Minister of India, heading the United Front (UF) coalition government.
The Janata Dal split in 1999 when some leaders left to ally with the Bharatiya Janata Party (BJP) -led National Democratic Alliance and formed the Janata Dal (United) party. The JD(U) was led by George Fernandes, while H D Deve Gowda emerged as the leader of the Janata Dal (Secular). The 2004 Assembly elections in Karnataka witnessed the revival of the party’s fortunes with JD(S) becoming a part of the ruling coalition in the state. Subsequently, party leader H D Kumaraswamy headed a popular coalition government in the state for 20 months.
Prominent leaders of the JD(S) are former Prime Minister H D Deve Gowda, H D Kumaraswamy - the Karnataka state president of JD(S), H D Revanna, N M Joseph and Mathew T Thomas. 
 In April 2015, the JD(S), the Janata Dal(United), the Rashtriya Janata Dal, the Indian National Lok Dal, the Samajwadi Party, and the Samajwadi Janata Party (Rashtriya) announced they would merge into a national Janata Parivar alliance in order to oppose the Bharatiya Janata Party (BJP). 
For the 2019 Lok Sabha Elections, JD(S) has declared that it will contest from 8 seats. In the 15th Karnataka Assembly Elections held in 2018, JD(S) won 37 seats. After a post-poll alliance with the Congress, H D Kumaraswamy was sworn in as the Chief Minister of the state.
Although JD(S) has hardly ever crossed a quarter of the strength of the Karnataka Legislative Assembly, the party has been a powerful player in the state's politics. In the 2019 Lok Sabha Elections, the Congress-JD(S) combine will fight the BJP in Karnataka. Interestingly, Congress President Rahul Gandhi kicked off his Lok Sabha campaign in Karnataka at a rally held in the outskirts of Bengaluru on March 31.