Gnanananda, also known as Swami Sri Gnanananda Giri, was an Indian guru and spiritual leader. He was the Chief Disciple of Sri Sivaratna Giri Swamigal and a leader (Peetathipathi) of the Jyotir Math, one of the four Maths established by Adi Shankara. Gnanananda belonged to the Giri Paramparai lineage, indicated by the suffix "Giri" in the names of the Peetathipathis.

He was considered a Mahayogi, Siddha Purusha, Himalayan sage, and Indian philosopher who followed the teachings of Advaita Vedanta due to his lineage. Gnanananda had several disciples, including Vidyananda, Triveni, and Dasagiri. He blessed Hari, also known as Haridhos Giri, to uplift and assist humanity through spreading devotion to the Guru.

Gnanananda was born in the early 19th century in the village of Mangalapuri in the North Kanara District of Karnataka. His parents were Venkoba Ganapati and SriMathi Sakku Bai. At a young age, he left home and became a disciple of Sivaratna Giri Swami, who gave him the name Pragnana Brahmachari. Later, Sivaratna Giri initiated him into the Giri order of Jyotir Mutt and bestowed upon him the monastic name Sri Gnanananda Giri.

After some time, Gnanananda renounced his position in the lineage of Jagadguru Totakacharya and retired to the Himalayas for penance. He spent many years practicing intense tapas (austerity) in the sacred location of Gangotri and the icy caves of the Himalayas. He embarked on extensive foot journeys, traveling throughout India, Tibet, Nepal, Burma, Sri Lanka, and Malaya, where he met numerous holy men along his pilgrimage.

After returning to India, Gnanananda established ashrams in different locations. The first ashram was in Attayampatti, Salem, followed by another in Siddhalingamadam near Villupuram. The most well-known ashram, called "Sri Gnanananda Tapovanam," is situated near Tirukkoyilur. In Tapovanam, Gnanananda built temples dedicated to various deities, including Gnanaganesa, Gnanaskandan, Gananapurisa, Gnanambika, Mahalakshmi, Gnanavenugopala, Gnanabhairava, and Gnananjaneya. Another ashram, known as "Pranavanilayam," was established in Yercaud, a hill station near Salem, and it served as a retreat for contemplatives with a focus on meditation and dhyana.

Swami Gnanananda Giri taught different paths based on the inclinations of his disciples. Some followed the path of knowledge (jñāna-marga), others the path of works (karma-marga), and some embraced the path of faith (bhakti-marga). His senior disciple, Vidyananda Giri, was a profound scholar who translated Shankara's commentaries on the Bhagavad Gita and the Upanishads into Tamil. He also provided Tamil versions of important Advaitic texts. Gnanananda emphasized the practice of Advaitic Nidhidhyasana and trained his followers in it. Another disciple, Satyananda, was associated with Franklin Merrell-Wolff and taught his method of "introceptive knowledge."

Recognizing that the path of Vichara and Nidhidhyasana was suited to only a few advanced aspirants, Gnanananda advocated stuti (praise), japa (repetition of a mantra), and nama sankirtan (singing the praises of God) for devotees at a less advanced level. He was well-versed in various modes of Bhajana Sampradaya (devotional practices) and believed that Hari Bhajana (devotion to God) was the easiest way for ordinary devotees to attain Moksha (liberation). Gnanananda chose Haridhos Giri to propagate the importance of Namasankeertanam (singing God's praises). Haridhos, who was initiated into sanyasa, carried his guru's sandals (Paadhuka) with him to all the holy places he visited. He established Mandalis and Samajams in various countries to promote the practice of Namasankeertanam.