"I would like to say that I think the success of AAP is a good indication and is a turning point in Indian politics," said Singh.
"It will give hope to the common man and revolutionaries on the streets that someday even they can be a part of Indian politics or even become a chief minister or prime minister someday," he said.
Digvijay Singh's comment came hours after Kejriwal was sworn-in as the seventh chief minister of Delhi on Saturday by Lt. Governor Najeeb Jung.
Along with Kejriwal, six other AAP MLAs were also administered oath of office and secrecy. The swearing-in ceremony was witnessed by tens of thousands of people, a majority of them AAP supporters, who cheered boisterously as the oath was taken. They also waved coloured balloons and the tricolor.
Earlier, Kejriwal and AAP MLAs traveled to the formal swearing-in ceremony at Delhi's Ram Lila Ground on the Delhi Metro.
Kejriwal became Delhi's youngest chief minister today at the age of 45. He has been asked to prove his majority in the state assembly by January 3. His first big challenge is to grapple with a 10 per cent hike in CNG prices, announced on Thursday.
Auto drivers in the city, who form a huge section of his supporters, have threatened a strike.
Kejriwal said yesterday he would see if the hike could be reversed. If that's not feasible, he said, auto fares are likely to increase. The former Indian Revenue Service official has promised to disassemble Delhi's VIP culture. Neither he, nor other AAP lawmakers will use the flashing red lights that give politicians' cars the right of way on roads. They have also refused large government bungalows and say they want small flats as their official accommodation.
It was those principles and a declaration of war against corruption that gave AAP 28 seats and a second place finish in the December 4 elections.
The BJP and allies got the most -- 32 -- while the Congress finished third with just eight seats.