Indian National Congress

In 2005, after differences with H. D. Deve Gowda, Siddaramaiah was expelled from JD (S). He wanted to revive a regional party "ABPJD" in the state after quitting the JD (S), but he did not because regional parties formed earlier in Karnataka had not survived.^[30] He subsequently garnered mass support from the backward classes and joined the Congress at a large public meeting held in Bangalore, in Sonia Gandhi's presence. He won the Chamundeshwari bypolls held in December 2006, by a margin of 257 votes against M. Shivabasappa of JD (S), despite a fierce campaign against him by Deve Gowda, Chief Minister Kumaraswamy and Deputy Chief Minister Yeddyurappa in the constituency.^[26] In the 2008 state Assembly elections, he contested from Varuna Constituency and was re-elected for the fifth time.^[31][32]

He won the 2013 election from the same constituency (Varuna) on 8 May 2013 and was reelected for the 7th time. He was elected as the leader of the Congress legislative party in the Karnataka assembly on 10 May 2013.^[33] He had previously announced that the 2013 Assembly election would be his last election,^[34] but in the 2018 Karnataka Legislative Assembly election, he left his safe Varuna seat for his son, and he himself went on to contest from two constituencies, i.e. Chamundeshwari and Badami, and faced stiff competition against GT Devegowda of JD (S) and B. Sriramulu of BJP respectively, both of which were new constituencies for him. He lost in Chamundeshwari, but won in Badami vidhan sabha seat beating BJP heavyweight Sriramulu with a narrow margin of 1,696 votes and he was reelected for the 8th time. Congress under his leadership then supported the Janata Dal (Secular) in forming the government in 2018 to keep BJP out of power. He was the chairman of coordination committee that coordinated the congress-JDS coalition govt under H. D Kumarswamy. After the resignation of 17 MLAs, leading to the downfall of the coalition government, Siddaramaiah took the leadership of the upcoming by-elections in Karnataka.^{[citation needed]}

The by-polls were held on 5 December 2019 for the 15 assembly seats. Though Siddaramaiah expressed his confidence in winning 12 out of the 15 contested seats, Congress managed to win only 2 seats and the JDS winning none of it.^[35] This was a major setback for his leadership and differences arose among his own party members questioning his leadership.^[36] Thus Siddaramaiah resigned as the Leader of the CLP and the Leader of opposition of the Karnataka Legislative Assembly on 9 December.^[37]

In the 2023 Karnataka legislative assembly election, Siddaramaiah contested from Varuna constituency and won. This makes his 9th election win. He was sworn in as Chief minister for the second time.^[38]

First term (2013–2018)

Siddaramaiah was elected as Chief Minister after Congress adopted a secret ballot to select the new chief minister.^[39][40] He led the Indian National Congress to victory by achieving an absolute majority of 122/224 seats in the 2013 Legislative Assembly election.^[41]

On 15 May 2018, he resigned from his position of the Chief minister of Karnataka, respecting the verdict of the 2018 Karnataka Legislative Assembly election.^[42] He also became the first chief minister of Karnataka to serve full 5 years term in 40 years, and the second in the history of the southern state after Devaraj Urs.^[43] He also holds the record of presenting state budget 13 times as a finance minister in Government of Karnataka. Despite allegations of mounting debt on state exchequer by the opposition, he is known for maintaining fiscal prudence within the ambit of Fiscal Responsibility and Budget Management Act of the state.^[44]

Second term (2023–present)

After the Congress emerged victorious in the 2023 legislative assembly election, Siddaramaiah was again elected Chief Minister, and D. K. Shivakumar was appointed his deputy.^[38] After the first cabinet meet, Siddaramaiah announced that all "5 guarantees" announced in the party's manifesto had been approved and would be brought into effect in the following cabinet meet.^[45] He also insisted that the officers roll back his "zero-traffic" protocol to avoid traffic congestion problems for the public.^[46] His council of ministers was named the following week and was reported that he would hold finance, cabinet affairs and all unallocated portfolios.^[47]

His cabinet approved reverting changes by the previous BJP government in school textbooks, which included removing lessons on RSS founder K. B. Hedgewar and Hindutva figure Vinayak Damodar Savarkar,^[48] launched a scheme providing free bus rides to women in the Karnataka state buses^[49] and announced implementation of other four pre-poll guarantees in the state budget.

In July 2023, he tabled the state budget for the record 14th time in state's history. He increased taxes on liquor, beer, stamp duty and registration of properties, and certain vehicle categories to fund the above mentioned schemes.^[50][51]

Other positions held

• Minister for Finance, Karnataka (1994)
• Minister for Animal Husbandry and Veterinary Services (1985)
• Minister for Sericulture and Animal Husbandry
• Minister for Transport
• Minister for Higher Education
• Member, Congress Working Committee
• He has represented Chamundeshwari, Varuna, and Badami Vidhan Sabha seats at various points of his career so far.