Jaitley (61) defended Modi vigrously when future appeared uncertain for the then Gujarat Chief Minister following 2002 riots and played a crucial rule in his rise to the top when voices of discontent, led by the likes L K Advani, grew louder.
And it is also an evidence of Modi's faith in him that despite his loss in Lok Sabha elections, the legal luminary was always being seen as a certainty in the Modi cabinet for a high profile ministry.
More of a strategist than a grassroots politician, Jaitley was a key helmsman in the party's 2014 campaign, now being recognised for its brilliance by even opponents, and was its key voice as the Modi juggernaut rolled on.
Through his blogposts, he keenly defended the personalised electioneering around Modi when other veterans like Sushma Swaraj, Murli Manohar Joshi besides Advani seemed to demur and even took gentle swipes at party leaders, including Sushma, when they disapproved of inclusion of tainted leaders like B S Yeddyurappa.
His detractors, though, would say his adroit political calculations were of not much personal help. He chose to fight his maiden Lok Sabha election from Amritsar and lost to Congress bigwig Amarinder Singh.
In the first BJP government under Atal Bihari Vajpayee, Jaitley was appointed Minister of State for Information and Broadcasting (Independent Charge) and later headed Disinvestment ministry (Independent Charge), a new Ministry created for to give effect to the policy of disinvestments.
He was the first Minister of Shipping following the bifurcation of the Ministry of Surface Transport and later headed Law& Justice where he gave shape to the policy of judicial reforms.
Seen as an articulate face of the party who is as much at ease in advocating market reforms as defending the traditional, at times orthodox, world view of the larger Sangh parivar, the senior Supreme Court lawyer at heart is a modernist who shares Modi's dictum of "minimum government, maximum governance".
Coming from a Punjabi Brahmin family with little political background, Jaitley chose the RSS' student body, ABVP, to plunge into politics as a student leader in 70s and became the Delhi University students union president in 1974.
He joined headlong into the anti-corruption movement kicked off by Jayaprakash Narayan which had led to the proclamation of Emergency by the then Indira Gandhi government. He was under detention for close to two years and joined Jan Sangh, the precursor to BJP, soon after.
Jaitley remained active in the party, which remained a fledgling outfit for much of the 80s, but also paid attention to his legal career where he shone.
Whether as a party spokesperson or organisation man entrusted with assembly election, Jaitley tasted success.
Not only the 2014 Lok Sabha polls, in Jaitley helped Modi win the Gujarat Assembly elections in 2002 with a landslide mandate. He also orchestrated Modi's 2007 campaign to help BJP return him to power.
The victory in 2007 showed that 2002 win was not a fluke and gave wings to Modi's national ambition. As Modi begins playing his prime ministerial innings, Jaitley is likely to be one of his most trusted counsellors.