By His own grace and at His own will Lord Swaminarayan manifested (born) Himself for the protection of religion and devotion in Kaliyuga for the welfare of numerous embodied souls. Lord Swaminarayan is the direct incarnation of Narayan Himself, at Whose will infinite universes create, sustain and destroy.
Thus His biological manifestation (birth) took place on 9th day of bright half of Chaitra month in V.S. 1837, known as Ramanavami in Chhapaiya, a village near Ayodhya in Uttar Pradesh. His father Dharmadev was Samavedi scholar Brahmin and mother was called Bhaktidevi owing to her devotional virtues and sacred qualities. After the passing away of His parents, when He was only eleven, the ascetic minded Neelkanth Varni later called Lord Swaminarayan, renounced His home with all its wealth and comforts and set out as a pedestrian pilgrim visiting Indian pilgrim spots and holy sites.
For the period of several years of His pilgrimage He performed severest penances for His devotees. As a part of His pilgrimage through Gujarat He happened to arrive in Loj village, situated midway between Somnath and Porbunder in Saurashtra. There He met Muktanandji, the chief disciple of great master Ramanand Swami; and later He came to have a face-to-face meeting with Ramanand Swami in a village called 'Piplana'.
Having taken birth in material body Lord Swaminarayan, too accepted Ramanand Swami, as His preceptor (Guru) and as per set religious rules got initiated, receiving Diksha at the hands of the great preceptor. Then the great preceptor handed over the control and management of entire Uddhava Religious Discipline to Lord Swaminarayan, Who inspired people to have Darshan of their family God instance without practising the Ashtang Yoga. Many people became His-words and His disciples after properly checking and testing the meditation process by the Lord. Without giving much importance to mysterious performances and miracles He engaged Himself in enriching the society by teaching them purity of thought, food, conduct by removing bad habits, addiction, blind faith, suspiciousness, immorality, corruption, luxury, inertness, theft, dacoity etc. Some scholars believed that there can be no incarnation of the God in Kaliyuga, He convinced them through proofs from the Geeta, the Bhagawat and other scriptures that Lord Swaminarayan is the Supreme incarnation and made them His wards and disciples. Lord Swaminarayan is the Supreme Brahman and the proof to this fact is found in ancient scriptures e.g.,
"Whenever religion suffers tormented regression I re-create myself to uproot irreligion and re-establish good religion to protect the gentle folk and to destroy the evil ones in every age". (Geeta 48-49)
You don't, but I know them all, for good many a birth yours and mine, have gone in the past (Geeta 45). According to the Geeta there is no such rule that incarnation should take place in Triyuga having 10 or 24 in number, other scriptures also offer similar description.
To protect religion I get another body, to eradicate irreligion I do manifest when the age demands (Shrimad Bhagawat) Brahmapurana says:
In Satyuga I manifest as Dattatreya, as Raghunandana in Treta Age, as Vasudeva in Dwapara, as Vrishatmaja (i.e. born of Shri Dharmadev) in Kaliyuga. Vishwaksena Samhita says :
Among all parts of universe I take birth on the Earth, I shall adore Vaikuntha adopting the name Sahajanand. All these scriptures prove Lord Swaminarayan as the Vedic acceptance of incarnated Supreme Reality.
Like the previous incarnations He did not destroy demons but He removed the demonic inclinations and turned demonic persons into divine ones. He uplifted and elevated the classes like Kathi-koli, Ahir, Shudra, Bhil, Moslims, illiterate peasantry etc. Apart from backward classes but great scholar-poets, officials, rulers and kings renouncing worldly life joined the Holy Fellowship, got initiated into asceticism, became stoics and set out for the spread of religion. Scholar saints offered valuable devotional prose-verse literature by offering volumes written in Sanskrit, Hindi, Brijbhasha and Gujarati. He opposed violent killing of animals before deities and in the Yajnas and offering scholarly counseling, stopped violence done in the name of religion. He advocated and popularised non-violent Yajnas. Lord Swaminarayan did welfare to many humans and animals by creating free-food centres, wells, step-wells, tanks and temples. He declared in Shikshapatri-47,
Both Narayan and Mahesh (Shiva) should be understood as one, both are proven forms of Brahman confirmed by Vedas. Thus he brought an end to the hostility between the Shaivas and Vaishnavas.
In order to bring complete chastity of character into the Holy Fellowship, He ordered that the temples, meeting assemblies and initiating rites should be quite separate for male and female followers. So he appointed married persons as chief of the Fellowship, from His own family line, and ordered the saints to observe eight types of aloofness from females. So that there would remain no possibility of corruption by crossing boundaries of self-control.
In order to prevent any blind tradition in the pure devotion of the Lord with a form (figure) he got large and beautiful temples constructed and wrote a sacred volume called Shikshapatri for the welfare of many souls even after His leaving the human body. Having fulfilled His mission of establishing the Bhagawat Dharma and the task of rejuvanising and revitalizing the ancient Vedic path, He left His mortal coil and assented to His divine abode Akshardham at Gadhpur (Saurashtra) on the 10th day of the bright half of Jyestha month of Vikram Samvat 1886; thenceforward He has been offering His divine vision in the form of an idol installed by Him in various temples in Holy Fellowship.