Swami Vivekananda, the nineteenth-century Indian Hindu monk, philosopher and spiritual mentor, is considered to be one of the most influential people of modern India and Hinduism. Celebrated particularly for his skill and power as a speaker, he was also one of the first and most successful missionaries of Vedanta to the Western world.

Rabindranath Tagore suggested that much could be learned about India through study of Vivekananda's works. Indian independence activist Subhas Chandra Bose regarded Vivekananda as his spiritual teacher. Mahatma Gandhi said that after reading the works of Vivekananda, his love for his nation increased a thousandfold. Barack Obama, the President of the United States, quoted Vivekananda's words in his speech delivered in India in November 2010. Jayalalithaa, the Chief Minister of Tamil Nadu said that Vivekananda inspired her to enter politics.

Vivekananda's birthday, on 12 January, is celebrated as National Youth Day in India. In 2012, a three-day world conference was organised by the Institute of World Religions to commemorate the 150th birth anniversary of Swami Vivekananda.

Influence on notable Indian people

After becoming a sannyasin in 1886, Vivekananda developed a deep desire to spread the message of “divine unity of existence and unity in diversity’ throughout the country. He travelled the length and breadth of India as a Parivrajaka ("wandering monk"). He travelled for two years, befriending many notable people and teaching his Advaita Vedanta philosophy. Many of them, such as Ajit Singh of Khetri in Rajasthan, the Dewan of Porbandar and Junagadh in Gujarat, the Raja of Ramnad in Madras, the Dewan of Mysore K. Seshadri Iyer, and the Maharaja of Mysore Chamaraja Wodeyar, encouraged him to travel to the United States to attend the Parliament of World Religions in Chicago, and gave financial support.

Indian nationalist Bal Gangadhar Tilak, the first popular leader of the Indian Independence Movement, observed:Twelve centuries ago Sankaracharya was the only great personality, who not only spoke of the purity of our religion, not only uttered in words that this religion was our strength and wealth, not only said that it was our sacred duty to preach this religion in the length and breadth of the world – but also brought all this into action. Swami Vivekananda is a person of that stature—who appeared towards the last half of the 19th century.

Rabindranath Tagore said "If you want to know India, study Vivekananda. In him everything is positive and nothing negative." According to Sri Aurobindo, Vivekananda was "a very lion among men, but the definite work he has left behind is quite incommensurate with our impression of his creative might and energy." Bal Gangadhar Tilak praised Vivekananda for taking the initiative to re-establish the glory of Hinduism. According to Bipin Chandra Pal, Vivekananda's message was "the message of modern humanity".

Mahatma Gandhi, at Belur Math on 6 February 1921, paid homage to Vivekananda: I have come here to pay my homage and respect to the revered memory of Swami Vivekananda, whose birthday is being celebrated today. I have gone through his works very thoroughly, and after having gone through them, the love that I had for my country became a thousand-fold. I ask you, young men, not to go away empty-handed without imbibing something of the spirit of the place where Swami Vivekananda lived and died.

During his journey from Japan to Canada on the ship Empress in 1893, Vivekananda met Jamsetji Tata and discussed with him the necessity of establishing a world-class scientific Institution in India. Consequently, Tata established the Indian Institute of Science, which gradually became one of the best-known research universities in India.

Indian independence activist Subhas Chandra Bose called Vivekananda a "full-blooded masculine personality – and a fighter to the core of his being". Bose said that under the "sacred influence" of Ramakrishna and Vivekananda his own life was awakened.

Jawaharlal Nehru, the first Prime Minister of Independent India, praised Vivekananda's personality and dignity and said that his heart carried fire: "it was no empty talk he was indulging in. He was putting his heart and soul into the words he uttered." Nehru also spoke of the influence Vivekananda had on his generation, particularly through his modern outlook that blended science and spirituality.Secular Nehru Helped Spread Vivekananda's Ideas, Times of India, 27 May 2020

Vinoba Bhave honoured Vivekananda for seeking to make Indians conscious of their strength during a time of widespread poverty and oppression, and for exhorting them to overcome their weaknesses. According to Bhave, the people of India were shrouded in tamas, ignorance and unwisdom, and unable to distinguish between weakness and non-attachment and peace. In this situation Vivekananda brought new light, emphatically teaching that "the same Soul resides in each and all", and that mankind could be served by remembering this.

According to Indian independence activist and social worker C. Rajagopalachari, who became the first Indian Governor General of India, Vivekananda saved Hinduism and India. Sarvepalli Radhakrishnan, the first vice-president and the second President of independent India, said that Vivekananda was born in a "critical period" when the nation and her people were collapsing in "despair, frustration and hopelessness". Vivekananda's teachings gave the people new hope and taught them to rely on spiritual resources.

According to Indian historian Ramesh Chandra Majumdar, Vivekananda preached the best parts of Hinduism and Indian spirituality to the world. At home, his ideals added a spiritual basis to Indian nationalism. Majumdar noted:

Though an ascetic, Vivekananda was a patriot of patriots. The thought of restoring the prehistoric glory of India by resuscitating among her people the spiritual vitality which was dormant, but not dead, was always the uppermost thought in his mind...

In 2013, former President of India Pranab Mukherjee suggested remembering Vivekananda's call to reconstruct India's national character. He said: Swamiji unhesitatingly appreciated the positive aspects and accomplishments of the Western Societies – and refrained from being dogmatic as he made his point, he was able to build a robust new bridge of understanding and goodwill for India. In so doing, he also opened a new dialogue between our peoples based on mutual acceptance.

Narendra Modi, the Prime minister of India, often invokes Vivekananda's name when promoting his political ideology. In April 2013, he visited Belur Math and meditated in the room of Vivekananda.

Jayalalithaa, the Chief Minister of Tamil Nadu, said that Vivekananda inspired her to enter politics. Mamata Banerjee, the Chief Minister of West Bengal, was inspired by Vivekananda's writings which she said helped her in the difficult times of her political career. Banerjee stated:

In the course of the several movements that I led, there would be moments of doubt. There were some who were critical of me and even I wondered that there were so many people who had pinned their hopes on me. What if I were to fail them? I would read books written by Swami Vivekananda to gather my strength.

Social activist Anna Hazare was motivated by the works of Swami Vivekananda and took inspiration for all the social work he did from Swami Vivekananda only. Arvind Kejriwal, anti-corruption campaigner and former Chief Minister of Delhi, also spoke of being inspired by Vivekananda. In a letter to the youth of India in 2015, he said:I always believed that truth is timeless. These words by Swami Vivekananda are as relevant today as they were when we had to struggle for freedom. And they will be just as relevant, decades after I have left this world.

Influence on non-Indian people Vivekananda, during and after his tour of western countries in Europe and the United States had profound influence on notable personalities, who either became his ardent devotees or friends and some even his ardent disciples and many of whom even became ascetics. Right at the beginning of his visit to Chicago to address the Parliament of World Religions Professor John Henry Wright of Harvard University, invited him to speak at Harvard. He pointed out to Vivekananda the necessity of going to the Parliament of Religions, which he thought would give an introduction to the nation. Wright's reasoning was "To ask for your credentials is like asking the sun to state its right to shine in the heavens". Some of such well-known luminaries are: Max Müller (Indologist), J. J. Goodwin, John Henry Barrows, Mark Twain, Sturdy, Romain Rolland, Sara Chapman Bull, his American mother and benefactor, Mary Hale, Josephine MacLeod, Christine Greenstidel (who later came to be known as Sister Christine), Maragaret Noble (Sister Nivedita in later years), William James, Josiah Royce, Robert G. Ingersoll, Nikola Tesla, Lord Kelvin, Harriet Monroe, Ella Wheeler Wilcox, Sarah Bernhardt, Emma Calvé and Hermann Ludwig Ferdinand von Helmholtz He initiated several followers : Marie Louise (a French woman) became Swami Abhayananda, and Leon Landsberg became Swami Kripananda,

American industrialist John D. Rockefeller reportedly made his first large donation for public welfare and later became a notable philanthropist after a meeting with Vivekananda. Vivekananda succinctly explained to Rockfeller that his philanthropy would only be a channel to help the poor and distressed people.

Vivekananda influenced French Opera singer Emma Calvé, who wrote in her autobiography:

It has been my good fortune and my joy to know a man who truly "walked with God," a noble being, a saint, a philosopher, and a true friend. His influence upon my spiritual life was profound. He opened up new horizons before me, enlarging and vivifying my religious ideas and ideals, teaching me a broader understanding of truth. My soul will bear him an eternal gratitude.

Vivekananda's life and works have influenced many scholars, writers, politicians worldwide. French writer Romain Rolland wrote that Vivekananda was "energy personified". Rolland felt "kingliness" was Vivekananda's characteristics, "He was a born king and nobody ever came near him in India or America without paying homage to his majesty." American writer, historian, philosopher Will Durant told, the speeches of Vivekananda were more "virile" than the ones delivered in the Vedic times.

The nationalist leader and the first president of independent Indonesia Sukarno said that it was Swami Vivekananda who inspired him to become strong and to serve God and mankind. Historian and Indologist Arthur Llewellyn Basham compared Vivekananda with other eminent religious figures of India such as Kabir, Adi Shankara, Chaitanya. Russian academician and public figure Eugene Chelyshev was an ardent admirer of Swami Vivekananda. He said: Reading and re-reading the works of Vivekananda each time I find in them something new that helps deeper to understand India, its philosophy, the way of the life and customs of the people in the past and the present, their dreams of the future... Chelyshev also predicted that the memory of Vivekananda will never fade away. Chinese scholar Huan Xin Chuan stated that Vivekananda was the most renowned social figure of modern China and Chinese socialists carefully study the works of Vivekananda.

Barack Obama, the President of the United States, quoted Vivekananda's words in his speech delivered in India in November 2010. He said: