The 45-year-old Magsaysay award winner will be facing enormous public expectations as he led AAP to a stunning victory capitalising on people's disillusionment with mainstream political parties.
"This is not my victory but that of the aam aadmi (common man). The aam aadmi will be chief minister, not me," he said after meeting Lt Governor Najeeb Jung.
Kejriwal is likely to have little over two months' time to deliver on his immediate priorities as model code of conduct for the Lok Sabha polls are set to come into force in March.
His running of government will be watched carefully as he led AAP to the victory in the December 4 assembly polls, criticising the "corrupt" Congress government on almost all aspects.
Kejriwal has also vowed to end the VIP culture like having cars fitted with red beacons and it will be interesting to see how the activist-turned-politician delivers on his promises.
As AAP decided to take outside support from Congress to form the government, it will be watched carefully whether he orders any probe into allegations of corruption against the Congress government.
Initially AAP had refused to take support from either Congress or BJP to form the government following which both the parties had accused it of shying away from the responsibility fearing that it would not be able to deliver on its promises.
In its manifesto, AAP had promised to slash power tariff by 50 per cent besides carrying out scrutiny of the accounts of the private power distribution companies.
The power tariff in Delhi is decided by the Delhi Electricity Regulatory Commission and it will be interesting to see how Kejriwal brings it down by half.