Sri Ramakrishna Paramahansa was an Indian Hindu mystic, saint, and religious leader in 19th century Bengal. Sri Ramakrishna experienced spiritual ecstasies from a young age, and was influenced by several religious traditions, including devotion toward the Goddess Kali, Tantra, Bhakti and Advaita Vedanta.

Sri Ramakrishna was born on 18 February 1836, in the village of Kamarpukur, in the Hooghly district of West Bengal, India, into a very poor, pious, and orthodox Brahmin family. Kamarpukur was untouched by the glamour of the city and contained rice fields, tall palms, royal banyans, a few lakes, and two cremation grounds. His parents were Khudiram Chattopadhyay and Chandramani Devi. According to his followers, Sri Ramakrishna's parents experienced supernatural incidents and visions before his birth. In Gaya his father Khudiram had a dream in which Bhagwan Gadadhara (a form of Vishnu), said that he would be born as his son. Chandramani Devi is said to have had a vision of light entering her womb from (Yogider Shiv Mandir) Shiva's temple.

The family was devoted to Hindu God Rama, and male children of Khudiram and Chandramani were given names that started with Ram or Rama: Ramkumar, Rameswar, and Ramakrishna. There has been some dispute about the origin of the name Ramakrishna, but there is "...evidence which proves beyond doubt that the name 'Ramakrishna' was given to him by his father..." Ramakrishna confirmed this himself, as recorded in "M"s diaries, "I was a pet child of my father. He used to call me Ramakrishnababu."Although Ramakrishna attended a village school with some regularity for 12 years, he later rejected the traditional schooling saying that he was not interested in a "bread-winning education". Kamarpukur, being a transit-point in well-established pilgrimage routes to Puri, brought him into contact with renunciates and holy men. He became well-versed in the Puranas, the Ramayana, the Mahabharata, and the Bhagavata Purana, hearing them from wandering monks and the Kathaks—a class of men in ancient India who preached and sang the Purāṇas. He could read and write in Bengali.

Rumors spread to Kamarpukur that Ramakrishna had become unstable as a result of his spiritual practices at Dakshineswar. Ramakrishna's mother and his elder brother Rameswar decided to get Ramakrishna married, thinking that marriage would be a good steadying influence upon him—by forcing him to accept responsibility and to keep his attention on normal affairs rather than his spiritual practices and visions. Ramakrishna himself mentioned that they could find the bride at the house of Ramchandra Mukherjee in Jayrambati, three miles to the north-west of Kamarpukur. The five-year-old bride, Saradamani Mukhopadhyaya (later known as Sarada Devi) (she is also considered as an avatar) was found and the marriage was duly solemnised in 1859. Ramakrishna was 23 at this point, but this age difference for marriage was typical for 19th century rural Bengal. They later spent three months together in Kamarpukur. Sarada Devi was fourteen while Ramakrishna was thirty-two. Ramakrishna became a very influential figure in Sarada's life, and she became a strong follower of his teachings. After the marriage, Sarada stayed at Jayrambati and joined Ramakrishna in Dakshineswar at the age of 18.
By the time his bride joined him, Ramakrishna had already embraced the monastic life of a sannyasi; the marriage was never consummated. As a priest Ramakrishna performed the ritual ceremony—the Shodashi Puja (in his room)–where Sarada Devi was worshiped as the Divine Mother. Ramakrishna regarded Saradadevi as the Divine Mother in person, addressing her as the Holy Mother, and it was by this name that she was known to Ramakrishna's disciples. Sarada Devi outlived Ramakrishna by 34 years and played an important role in the nascent religious movement.

While Ramakrishna was a temple priest at Dakshineswar, itinerant sadhus could come and stay for a while, practicing their particular mode of worship. Several of these people became Ramakrishna's teachers in the various schools of Hinduism. He had grown up practicing Bhakti (devotion) to Rama. His duties as priest at the Dakshineswar temple led him to practice worship of Mother Kali.

Totapuri and Vedanta
In 1865, Ramakrishna was initiated into sannyasa by Totapuri, an itinerant Naga Sannyasi (monk) of Mahanirvani Akhara who trained Ramakrishna in Advaita Vedanta, the Hindu philosophy which emphasises non-dualism.
Totapuri first guided Ramakrishna through the rites of sannyasa—renunciation of all ties to the world. Then he instructed him in the teaching of advaita—that "Brahman alone is real, and the world is illusory; I have no separate existence; I am that Brahman alone." Under the guidance of Totapuri, Ramakrishna reportedly experienced nirvikalpa samadhi, which is considered to be the highest state in spiritual realisation. He remained in that state of non-dual existence for six months without the least awareness of even his own body.
Totapuri stayed with Ramakrishna for nearly eleven months and instructed him further in the teachings of advaita. Ramakrishna said that this period of nirvikalpa samadhi came to an end when he received a command from the Mother Kali to "remain in Bhavamukha; for the enlightenment of the people". Bhavamukha being a state of existence intermediate between samādhi and normal consciousness.

Vivekananda portrayed Ramakrishna as an Advaita Vedantin. Vivekananda's approach can be located in the historical background of Ramakrishna and Calcutta during the mid-19th century. Neevel notes that the image of Ramakrishna underwent several transformations in the writings of his prominent admirers, who changed the 'religious madman' into a calm and well-behaving proponent of Advaita Vedanta. Narasingha Sil has argued that Vivekananda revised and mythologised Ramakrishna's image after Ramakrishna's death. McDaniel notes that the Ramakrishna Mission is biased towards Advaita Vedanta, and downplays the importance of Shaktism in Ramakrishna's spirituality. Malcolm McLean argued that the Ramakrishna Movement presents "a particular kind of explanation of Ramakrishna, that he was some kind of neo-Vedantist who taught that all religions lead to the same Godhead."