In his first 15 months in office, the right-wing premier has travelled to some two dozen countries, burnishing ties with allies and rivals alike in a campaign to ensure India punches its weight on the world stage and offsets China's rise.
Critics say "Modiplomacy" has yielded little and accuse him of taking his eye off domestic affairs as he struggles to enact key reforms.
But even opponents admit Modi has injected some vigour into India's pursuit of the world stage.
As well as meeting leaders of heavyweights such as the United States, Germany, Russia, Brazil and China, Modi has reached out to neighbours, becoming the first Indian leader to visit Sri Lanka in three decades.
Read: Modi addresses thousands of Indian expats at Dubai cricket stadium
He is also rolling out the red carpet for smaller countries, hosting 14 heads of state from Pacific islands on August 21 and a summit with African leaders in October.
Shashi Tharoor, a minister in the previous Congress government, says Modi has shamelessly reversed his stance on a host of foreign policy issues but acknowledges he brings "personal energy" to the table.
"He is doing well, says the right thing in whichever country he goes to and leaves a positive impression," Tharoor, a former UN deputy secretary general, told AFP.
Given Modi's track record, few had anticipated diplomacy would be one of his top priorities.
He first drew the attention of foreign governments during a frenzy of communal violence in Gujarat soon after becoming chief minister in 2002. He was consequently blacklisted for a decade by the US and European Union.
During last year's election campaign, Modi burnished his credentials as a hardline nationalist by berating China's "expansionist mindset".
But soon after taking power he invited Xi Jinping for the first visit by a Chinese leader to India in eight years before his own visit to Beijing in May.
He has also accepted an invitation from his counterpart Nawaz Sharif to attend a summit in India's arch rival Pakistan, another target of his ire on the campaign trail.
C. Raja Mohan, author of a new book on Modi's foreign policy, says the premier's overriding goal is to "expand India's sphere of influence", not least by joining China as a permanent UN Security Council member.
A recent UN survey predicted India's population would surpass China's by 2022 and its economy is growing faster than almost all other major countries.
Modi spent 13 years running Gujarat, a coastal state with a reputation as outward-looking and entrepreneurial.
"With Modi, I think that there is a Gujarati pragmatism that dictates how to think about the world," Mohan told AFP.
"He is conscious of India's changed position in the international system, that India can be a confident player which is aware of its growing weight in the international system."
On his way back from China, Modi paid the first visit by an Indian leader to Mongolia, and dropped into five of the resource-rich Central Asian republics which have long-standing relationships with Beijing.
Analysts say similar thinking explains Modi's invitation to the African and Pacific leaders, many of whom have received soft loans from China.
"If you look at his visit to Central Asia and the engagements with the Pacific Island nations and the Africa summit, then you can say that China, resources and a general effort to increase India's strategic footprint are all common threads," analyst Ashok Malik told AFP.
China has long cultivated ties with African countries as it seeks resources that India may also need as its development quickens.
"India has historically had good relations with Africa but lost out (to China) in the last 15-20 years," said Malik of Delhi's Observer Research Foundation.
Modi's greater involvement in South Asia is widely seen as a pushback against China's overtures towards India's neighbours, such as Sri Lanka.
Read: Modi urges unity against 'terror-harbouring states' in veiled jibe at Pakistan
India won kudos in Nepal after April's earthquake for its aid response, which dwarfed China's.
Demonstrating his growing self-assurance on the world stage, Modi is now more comfortable delivering speeches and talking to his counterparts in English, after initially speaking only in Hindi.
S. Jaishankar, India's foreign secretary, says recent initiatives "speak of greater confidence".
"Are we content to react to events or should we be shaping them more, on occasion even driving them?" he asked in a speech.
"Perhaps it is time to reassess our ability to drive and lead on global issues, and be active and nimble rather than neutral or risk-averse."
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