A new government has taken office in the southern Indian state of Karnataka headed by a regional party in coalition with the main opposition BJP.
Mr Kumaraswamy has pledged to improve Bangalore's infrastructure
HD Kumaraswamy of the Janata Dal (Secular) Party has been sworn in as the state's new chief minister.
The BJP is now in government in southern India for the first time and it is seen as a boost for the party.
Karnataka is a key Indian state, and its capital, Bangalore, is the hub of India's booming InfoTech industry.
The Janata Dal was part of the previous government but withdrew support to the Congress party-led coalition, leading to a fortnight-long political crisis in the state.
The 46-year-old Mr Kumaraswamy is the son of former Prime Minister HD Deve Gowda.
The BBC's Sunil Raman in Bangalore says running the new coalition will not be easy as the two parties have vastly different ideologies.
The political upheavals were triggered by a split in the Janata Dal (Secular) party, part of the current coalition.
The previous chief minister, Dharam Singh, resigned late last month after failing to woo the defectors back into the governing coalition.
Mr Dharam Singh failed to woo back the defectors
The last elections in 2004 had thrown up a split verdict with no party gaining a majority in the 224-member state assembly.
The BJP had emerged as the largest party with 79 legislators, but Congress with its 64 members aligned with 58 Janata Dal (Secular) to form the government.
The government lasted for 20 months before the recent split.
The previous government was plagued by controversies over Bangalore's deteriorating infrastructure.
Many InfoTech companies expressing concern about the future of the city as India's InfoTech centre.
Mr Kumaraswamy has allayed such fears, saying improving Bangalore's infrastructure will be a priority.
Present-day Bangalore is a city of 6.5m people, often referred to as India's Silicon Valley.
It is home to more than 1,500 info-tech companies and accounts for a third of the India's $17bn software and business process outsourcing industry.