60-year-old KCR took oath as chief minister along with his son K T Rama Rao, nephew T Harish Rao and nine others administered by governor E S L Narasimhan at Raj Bhavan.
Celebrations erupted in the state to mark the historic event that came after a long-drawn-out process of bifurcation of Andhra Pradesh.
Nine other cabinet ministers were sworn in the new state -Mohammed Mahmood Ali, T Rajaiah, Nayani Narasimha Reddy, Eatela Rajender, Pocharam Srinivasa Reddy, T Padma Rao, P Mahender Reddy, Jogu Ramanna and G Jagadish Reddy.
The swearing-in ceremony was not without controversies, as chief minister-designate of successor state of Andhra Pradesh N Chandrababu Naidu skipped it, in what is seen as first signs of discord between the two “regional satraps”.
Sources said Telugu Desam Party president was peeved that there was neither a personal invitation nor a telephone call; it was said to be a routine invitation from the administration.
Naidu, who was swept to power in the successor state of Andhra Pradesh, is slated to be sworn in as Chief Minister on June eight at a ceremony to be held between Vijayawada and Guntur.
Welcoming the formation of Telangana, Prime Minister Narendra Modi promised complete central support to help take the state to newer heights of progress.
He congratulated KCR on becoming the first chief minister of the 29th state and expressed best wishes to its people.
President’s Rule imposed in united Andhra Pradesh was revoked partially to facilitate swearing in of a government in the state.
However, it would continue to be in force in the residuary Andhra Pradesh till Naidu takes over as chief minister.
Earlier, Narasimhan was sworn in as the first governor of Telangana.
Andhra Pradesh high court chief justice Kalyan Jyoti Sengupta administered the oath to Narasimhan, who will be the common Governor of Telangana and residuary Andhra Pradesh.
Hyderabad will be the joint capital of Telangana and residuary Andhra Pradesh.
KCR started his career with the youth Congress party in Medak district, controlled by Sanjay Gandhi in the 1970s. He joined the TDP in 1983 and contested against A Madan Mohan and lost that election.
KCR won four consecutive assembly elections from Siddipet between 1985 and 1999. He also served as the deputy speaker of the Andhra assembly.
TRS was part of the United Progressive Alliance coalition government, led by Congress. The party later withdrew from the coalition, saying that the Alliance was not taking forward its demand for a separate Telangana state.
In 2004, he fought the Lok Sabha polls and went on to become a Union Cabinet minister of Labour and Employment in the UPA-1 government at the Centre.
He resigned in 2006 over the Telangana issue. In 2009, he fought and won the Mahbubnagar Lok Sabha by-election for the TRS. The party fought the general elections as part of the opposition coalition.
TRS secured majority in recent Legislative Assembly elections by winning 63 of the 119 seats in Telangana region.
Euphoria swept the new state with TRS activists and supporters painting Hyderabad pink, the colour of TRS flag, by installing huge cut-outs, banners, festoons and balloons hailing their leader.
Cultural programmes have been planned and a dazzling display of fireworks would be held tonight at People’s Plaza and Tank Bund at the picturesque Hussain Sagar lake to celebrate the occasion.