Born in Rangoon (now Yangon, Myanmar) Mr Rupani, 61, joined an RSS shakha as a schoolboy, before graduating to the BJP via the Sangh's students wing - the Akhil Bharatiya Vidyarthi Parishad (ABVP).
Though Prime Minister Narendra Modi was the BJP's face in the high-octane election campaign in his home state, Mr Rupani, belonging to the relatively small Jain community, steered the party machinery in Gujarat, neutralising the incumbency factor against his government and surviving quota stir by the Patidar community, the bedrock of the party's support base.
That he also successfully contained disenchantment with the government over farm distress in some parts of the state, and economic slowdown due to demonetisation and roll out of the Goods and Services Tax (GST), also stood him in good stead.
Despite the BJP's tally falling below 100 in a long time, ,Mr Rupani's selection also suggested that the top party leadership wanted continuity before the 2019 Lok Sabha polls.
Though only a second-time MLA, he made a mark as an able administrator.
Mr Rupani, who worked mostly in the party organisation in Gujarat, fought his first Assembly election in 2014, winning a bypoll from Rajkot West. This time he won from the same seat with an impressive margin of over 53,000 votes.
A bachelor of law, Mr Rupani was a Rajya Sabha member between 2006 and 2012.
It was under him as chairman of the Gujarat Tourism Development Corporation in 2006 that the hugely successful advertisement campaign 'Khushboo Gujarat Ki', featuring megastar Amitabh Bachchan, was launched to promote the state as a tourism hotspot.
He was also the chairman of the Gujarat Municipal Finance Board in 2013.
When the Rajkot West seat fell vacant in October 2014 after Speaker of the Assembly Vajubhai Vala was appointed the Karnataka Governor, Mr Rupani won the bypoll.
On February 19, 2016, he was appointed the chief of the Gujarat BJP. It was seen as a victory for the Amit Shah camp in the state unit.
When the state's first and only woman chief minister Anandiben Patel resigned in August 2016 following allegations of inept handling of the Patidar and Dalit agitations, Mr Rupani was catapulted to the hot seat.
Mr Rupani honed his political skills in the crucible of the Gujarat Navnirman agitation, a socio-political movement in 1974 by students and the middle-class against economic crisis and corruption in public life.
It soon spread elsewhere, particularly in Bihar, where socialist legend Jayaprakash Narayan gave a call for 'Total Revolution'. The movement finally led to the fall of Indira Gandhi government and installation of the first non-Congress dispensation at the centre under Morarji Desai.
Mr Rupani, who was then with the ABVP, was jailed for nearly a year during Emergency.
As the mayor of Rajkot in 1996-97, he endeared himself to people of the city with his initiatives for improvement of the civic infrastructure.
Mr Rupani's mettle as a politician will be tested again in the 2019 Lok Sabha polls when PM Modi bids for a second shot at power. Delivering Gujarat to the BJP is the least he would expect from Amit Shah's man in Gandhinagar.