One is an IITian and former IRS officer who is surrounded by a mix of NGO activists, old style socialists and secular fundamentalists; the other is an RSS pracharak turned PM-in-waiting whose parivar includes the saffron brotherhood, hi-tech whiz kids and captains of industry.
It is unlikely that the ideologically contrasting Kejriwal and Modi will ever break bread, but both have one thing in common: both are 'gatecrashers' in a status quoist political system. Both, in different ways, claim to be change agents to be 'feared' by the incumbent government.
In a recent CNN IBN survey done by CSDS, more than half of those who preferred Kejriwal for Delhi chief ministership, opted for Narendra Modi to be their prime ministerial choice.
In particular, the young and the restless - the 18 to 25 age group which appears to have been drawn to Modi's machismo - liked Kejriwal's 'anti-establishment' image too. Almost a bit like the youthful attraction for the Salim-Javed 'angry' heroes of the 1970s.
Listen to their high pitched rhetoric in speeches. Modi speaks of being the son of a tea-shop owner who wants to take on the 'Shehzada'; Kejriwal talks of being the 'aam aadmi' representative who will 'sweep away' brashtachar with his jhadoo.
Both essentially claim to have a similar enemy: the Lutyens elite of Delhi which has ruled the country for much of the last 60 years. Both are looking to position themselves as the outsiders who are not members of any cosy club of privilege.
The attraction of such 'outsiders' is obvious. Over the last several years, there has been a growing, legitimate anger against the VIP 'khaas aadmi' culture.
The 'lal batti' of a government car in particular has come to symbolise a decrepit ruling class which is seen to be distant from real India. Moreover, the VIP culture is seen to represent an unequal state in which some are more privileged than others.
By repeatedly questioning the prevailing political order, both Kejriwal and Modi have tried to create the basis for a new form of 'us' versus 'them' anti-establishment politics.
For the highly judgmental Kejriwal, the 'establishment' includes both the national parties, as well as corporate India and anyone who is seen to be above a certain income level.
For the Hindutvawadi Modi, the 'establishment' is primarily the Nehru-Gandhi family and their supporters.
It should come as no surprise then that Kejriwal's strongest support is increasingly coming from lower income groups, including those in the jhuggi-zopdis, to whom he offers all kinds of goodies, from free water to electricity at half price.
And while NRIs keen to identify with the 'Motherland' may fund the Aam Aadmi Party (AAP), the party's social base is now dominated by those who feel left out of the growth engine.
Modi is also a favourite of long distance NRI nationalists, but is, by contrast, most attractive to those who have benefitted from two decades of economic liberalisation.
This middle and high income socio-economic group feels betrayed by the Congress and Manmohan Singh, and fears that a few more years of sloth, corruption and pro-poor largesse will permanently derail the gravy train of sustained growth.
Aspirational India - be it in Dalal Street or even in the bazaars of small town India - looks at Modi as someone who offers hope of an economic turnaround.
For this large urban, mainly upper and middle caste Hindu constituency, the 2002 riots and Hindu-Muslim relations are a distant memory, their dominant concern is their own financial future.
The Modi-Kejriwal comparison extends to their leadership style as well. Both are larger than the parties they represent and fiercely individualistic in their approach.
In a way, both are their own high commands who are driving their campaigns through strong personality driven politics. We hardly know anything of the other 69 candidates of the AAP in the Delhi elections just as none of the other Cabinet ministers in the Gujarat government really matter.
Excellent communicators, both have also used the media with remarkable astuteness. Be it television or social media, the AAP and the Modi brigade have been a step ahead of their Congress rivals.
The media was oxygen for the Anna movement in 2011 which first catapulted Kejriwal from just another anti-corruption crusader into a national figure.
Modi too, has benefitted from the relentless media coverage of his every move, emerging as by far the most watched politician in the country today. And if Modi bhakts are quick to counter any criticism of their icon on social media, so are the AAP groupies.
In fact, their abusive responses at times only confirm that intolerance is not the sole preserve of any particular ideology.
The big question is: will Modi and Kejriwal succeed in their respective missions? There are no magic wands in politics and electoral arithmetic can often be far more complex than voter chemistry.
What is clear, though, is that both Kejriwal and Modi have chosen to capitalise on a growing fatigue with the existing ruling arrangement. Their success will depend on just how widespread this mood for change really is.
Which is why the Delhi election results are perhaps the most crucial and exciting of the five states going to the polls this winter. If Kejriwal does well in Delhi, it may well be the first real sign that urban India is moving firmly away from the Congress.
And that can only be good news for the Modi campaign nationally. On the other hand, a failure for Kejriwal could, ironically, be a warning for the BJP's prime ministerial nominee not to get swayed by media hype.
Postscript: There is one other major difference between Kejriwal and Modi which is in their sartorial preferences. While the AAP leader prefers the crumpled white shirt and Gandhi topi, Modi likes well-starched expensive kurtas and varied headgear. In politics, there is no set wardrobe for success!
Rajdeep Sardesai is editor-in-chief, IBN 18 network
The views expressed by the author are personal