Krishnamacharya was born on 18th of November 1888 in Muchukundapuram, in Chitradurga district of Karnataka State in India, to an orthodox Iyengar family. His parents were Sri Tirumalai Srivinasa Tattacharya, a well-known teacher of the Vedas, and Shrimati Ranganayakamma. He was the eldest with two brothers and three sisters. At the age of six, he underwent upanayana.  He then began learning to speak and write Sanskrit, texts such as the Amarakosha and to chant the Vedas under the strict tutelage of his father.

Unfortunately at the age of ten, Krishnamacharya lost his father, and the family had to move to Mysore, the second largest city in (Karnataka), where Krishnamcharya's great-grandfather H.H. Sri Srinivasa Brahmatantra Parakala Swami acted as the head of the Parakala Mutt. In Mysore, Krishnamacharya began a more formal schooling at the Chamaraj Sanskrit College and in the Maṭha. He made a practice of debating on the subjects of the Shastras with the professors and visiting Pandits. He passed his Vidvan examination in Mysore, where he had studied Vyakarana, vedanta and tarka.

At the age of sixteen, Krishnamacharya had a strange dream in which his ancestor, the legendary yogi and Sri Vaishnava saint Nathamuni directed him to go to the town of Alvar Tirungari, in the neighboring state of Tamil Nadu. Krishnamacharya obeyed the dream and traveled there. As he later told, when he arrived at his destination, he fell into trance and found himself in the presence of three sages. He requested them to instruct him in the Yoga Rahasya, a long lost yogic treatise by Nathamuni. One of the sages, whom he later identified as Nathamuni himself, started to recite the text. When Krishnamacharya later woke up from the trance, he could recall every single verse of this legendary treatise lost long ago.

During all this time Krishnamacharya continued to practice the yoga that his father had taught him as a young boy. Krishnamacharya had also learnt Yoga from shri Babu Bhagwan Das, and passed the Sankhya Yoga Examination of Patna. Many of his instructors recognized his abilities in this area and supported his progress and asked that he teach their children. During his vacation time he would take pilgrimages into the Himalayas. At the suggestion of Gaṅgānāth Jhā, he decided to find Yogeshwara Ramamohan Brahmachari, a yoga teacher rumored to live in the mountains beyond Nepal. He had to obtain the permission of the Viceroy, Lord Irwin; who was then suffering from diabetes. At the request of the Viceroy, he travelled to Simla and taught him yogic practices for six months. The viceroy developed respect and affection for him, and made all arrangements for his travel to Tibet in 1919; supplying three aides and taking care of the expenses.

Eventually, after two and a half months of walking, Krishnamacharya found Sri Brahmachari's school which consisted of a cave at the foot of Mount Kailash. Ramamohana Brahmachari was a family man, and Gaṅgānātha Jhā had written to him earlier. He spent seven and a half years studying the "Yoga Sutras of Patanjali, learning asanas and pranayama, and studying the therapeutic aspects of yoga" He was made to memorize the whole of the Yoga Kuruntha in the Gurkha language. As tradition holds, at the end of his studies with Sri Ramamohan, Krishnamacharya asked what payment would be - Ramamohan responded that Krishnamacharya was to "take a wife, raise children and be a teacher of Yoga".

Krishnamacharya was known to be able to voluntarily stop his visible heart beat/ pulse for over two minutes, probably by drastically reducing venous return to the heart.

Krishnamacharya taught Yoga to people of all religions. He always took time to understand the religion and the culture of the people he taught. For example, when he was invited to teach the Nizam of Hyderabad, he spoke to him in Urdu. The Nizam was so impressed that his entire family practiced Yoga.

K. Pattabhi Jois and BKS Iyengar teach based on their own experiences with Krishnamacharya in the 1930s in Mysore, when they were both young men; their styles are reflective of yoga that is appropriate to younger students and thus heavily emphasise asana practice. However, teachers such as T.K.V Desikachar, A.G Mohan and Srivatsa Ramaswami teach a broader part of Krishnamacharya's teachings, noting that yoga is more than just asana and must be tuned to the student, taking account of health, energy, physique, gender, place and age.