From 1999 to 2004, he headed India’s first non-Congress party government that lasted a full five-year term. This was a significant achievement in a country where the Indian National Congress party — the party of the country’s first prime minister, Jawaharlal Nehru — had dominated politics since independence from Britain in 1947.
Weeks into his second stint as prime minister, Mr. Vajpayee shocked the world in May 1998 with five underground nuclear tests, prompting international sanctions, rattling neighbors and setting off an arms race with archrival Pakistan.
India first conducted a test in 1974 but had long maintained that its nuclear program was meant for peaceful purposes. The new tests established India as an overt nuclear-weapon state.
Students from an art school place flower petals around a painting of former Indian prime minister Atal Bihari Vajpayee in Mumbai on Thursday. Vajpayee died Thursday at age 93. (Rajanish Kakade/AP)
“We will not use these weapons against anybody. But to defend ourselves, if the need arises, we will not hesitate,” Mr. Vajpayee said in a speech to his supporters at the time.
Pakistan followed with its own nuclear tests, prompting fears from analysts who began describing the Indian subcontinent as the world’s likeliest nuclear flash point. Domestically, the tests made Mr. Vajpayee’s party immensely popular and bolstered its image of being tough on national security.
In the immediate aftermath of the testing, President Bill Clinton denounced India for undermining the stability of South Asia and directly challenging “the firm international consensus to stop nuclear proliferation.”
But Mr. Vajpayee worked discreet diplomacy behind closed doors and set in motion a friendly dialogue with Clinton, who went to India in 2000, the first visit by a U.S. president to the country in more than two decades.
Mr. Vajpayee, known as an avuncular politician, was credited with helping bring mainstream acceptance to his Hindu nationalist Bharatiya Janata Party (BJP).
The party had struggled for many years before gaining political prominence in the 1990s by carefully nurturing religious pride and projecting the Congress party as being softer on the country’s Muslim minority group.
The BJP became the single-largest party in the elections in 1996 and 1998 but did not win in enough voting districts to form a majority in the lower house of Parliament. As a result, Mr. Vajpayee’s government in 1996 lasted just 13 days, and his second term as prime minister lasted 13 months in 1998 and 1999.
But later, it was Mr. Vajpayee’s personal charisma and moderate image that helped the BJP stitch together a broad-based coalition of smaller, disparate regional parties. Between 1999 and 2004, he deftly managed the unwieldy coalition government of fractious partners.
He deployed similar skills to begin a new peace process with his Pakistani counterpart, Nawaz Sharif, and traveled to Lahore in northeastern Pakistan by bus in February 1999. But the effort was undermined three months later when the Pakistani army and separatist militants launched an offensive in the Kargil mountains of Kashmir, a Himalayan region claimed by the two South Asian neighbors.
About 1,200 troops from both countries were said to have died in the short conflict; Sharif would later say that up to 4,000 Pakistanis died in the fighting.
Mr. Vajpayee went on to parlay the Kargil events into victory at the polls, winning another term in October 1999 general elections.
Sharif was soon removed in a military coup by Gen. Pervez Musharraf as Pakistan sank into political instability. While condemning the coup, Mr. Vajpayee continued to negotiate with Islamabad. This resulted in a 2001 peace summit in Agra, the city of the Taj Mahal, but it failed to get the peace process moving.
The biggest blot on his term was the February 2002 religious rioting between Hindus and Muslims in the western state of Gujarat. A government estimate said 1,024 people, mostly Muslims, were killed.
The government in Gujarat was then headed by the Hindu nationalist hard-liner Narendra Modi — a future prime minister who at that time was widely accused of not doing enough to stop the attacks on Muslims by Hindu mobs. The reprisal violence erupted after some Muslims set fire to a train coach, killing 59 Hindus.
At a news conference, Mr. Vajpayee told Modi to carry out the “duty of the ruler,” which was widely interpreted by many as a public rebuke. More than a decade later, Modi overcame the taint of that episode and was swept to power in the 2014 general election.
Mr. Vajpayee continued privatizing and reshaping the economy during his third term, a process set in motion in 1991 by the previous Congress party government. In 2004, the BJP campaigned on his economic accomplishments, coining the slogan “India Shining.”
But the voters apparently did not feel as prosperous as the BJP thought they were, and Mr. Vajpayee was dislodged. He retired from active politics the next year.
Atal Bihari Vajpayee was born in the central Indian city of Gwalior on Dec. 25, 1924. His father was a schoolteacher and Hindu scholar.
As a teenager, he was drawn to the Hindu nationalist organization Rashtriya Swayamsevak Sangh (RSS), a controversial group that was banned briefly after a former member assassinated the Indian independence-movement leader Mohandas Gandhi in 1948. Over the years, Mr. Vajpayee brought back to Hindu nationalists some of the respectability they had lost since Gandhi’s assassination.
After graduating from what was then called Victoria College in Gwalior, Mr. Vajpayee earned a master’s degree in political science from Dayanand Anglo-Vedic College in Kanpur. He dropped out of law school to edit an RSS magazine.
In 1951, Mr. Vajpayee joined the newly formed political party called the Bharatiya Jana Sangh, the predecessor of the BJP. Later, he became the party’s leader and began a long parliamentary career. He served as foreign minister in the late 1970s in a coalition government. Under Mr. Vajpayee’s leadership, the old Bharatiya Jana Sangh was reborn as the BJP in 1980.
An orator who peppered his speeches with wit and lines from his own poems, Mr. Vajpayee was viewed more as a kind of philosopher-king and less as a hard-nosed politician.
Mr. Vajpayee, who never married, was known to like good meat and expensive whiskey, and he made several public denials over charges of eating beef, a serious allegation against a Hindu leader.