"It is an honour and a privilege for me to assume this responsibility...I look forward to the opportunity to serve the group in this new role for the years to come and seek support from everyone so that we can collectively make it happen," he said.
The new Tata chief began his job chairing the Tata Sons Board meeting at Bombay House, sources said.
Chandrasekaran served TCS for three decades as it rose to become the largest IT company in the country and also the crown jewel for Tata Sons -- the group holding company which is majority-owned by philanthropic trusts set up by the Tata family.
Chandra reached the group headquarters around 9:15 am and within a few minutes, Ratan Tata and other board members also arrived.
Yesterday, Chandra chaired the TCS Board meeting which declared the country's largest share buyback worth Rs 16,000 crore.
Chandra succeeds 79-year-old Ratan Tata, who had come back as the interim chairman of the group after a surprise ouster of Cyrus Mistry as the chairman on October 24 last year.
His removal led to a bitter corporate battle with Mistry coming out with not-so-palatable allegations about the functioning of the diversified group, including personal allegations against Ratan Tata himself.
The Tatas had rubbished all allegations and wrested control after removing Mistry from directorships at group companies
and finally the holding company.
The group relies heavily on TCS and the acquired British automaker JLR, whereas other traditional businesses that made it a force to reckon with like steel, auto and hospitality, are not at the top of their mark, according to industry watchers.
Marathon runner Chandrasekaran is the first non-family and non-Tata to lead the conglomerate.