At Seva Pratisthan

From 1953 to 1958, he was in Shillong centre, where he worked under the guidance of Swami Saumyanandaji Maharaj. During this period he also organized flood relief operations in Assam a couple of times. Keenly interested in service to sick and suffering people, he was posted to the Mission's hospital centre, Ramakrishna Mission Seva Pratishthan, Kolkata, in 1958. There he worked during the first 5 years as its Assistant Secretary under Swami Dayanandaji and then as its head for 22 years. He worked to develop the services of Seva Pratishthan to cater to the medical needs of more and more people belonging to poor and low-income sections of the society and converted the original small maternity hospital into a 550-bed, modern, well-equipped hospital.

Swami Gahananandaji at Belur Math Durga Puja

At Belur Math

He was elected a trustee of the Ramakrishna Math and Member of the Governing Body of the Ramakrishna Mission in 1965. In 1979, he was appointed an Assistant Secretary of the twin organizations. He became the General Secretary of the Math and Mission in 1989 and continued in that post for 3 years till 1992 when he became a Vice-President of the Order. In 1993, he represented the Ramakrishna Order at the commemorative function organized by the Council for a Parliament of the World's Religions in Chicago (and attended by 6500 people from all parts of the world) to celebrate the centenary of Swami Vivekananda's historic appearance at the World Parliament of Religions. From 1992, he was also simultaneously the head of Ramakrishna Math (Yogodyan) at Kankurgachhi, Kolkata.

As President

As a Vice-President of the Math and Mission, Swami Gahananandaji travelled extensively in various parts of the country and visited many branches of the Order. He also visited at different times various places in the USA, Canada, England, France, Switzerland, the Netherlands, Russia, Australia, Japan, Myanmar, Sri Lanka, Bangladesh, Singapore, Malaysia and Mauritius. In all these places, he spread the message of Vedanta and Ramakrishna, Sarada Devi and Vivekananda.

Gahanananda was elected the president of the Ramakrishna Math and Ramakrishna Mission in May 2005.

He died on Sunday, 4 November 2007 at 5.35 pm after a prolonged illness. He had been admitted to the Ramakrishna Mission Seva Pratisthan hospital in Kolkata on 4 September.

Thousands of devotees queued up to pay their last respects at Sanskriti Bhavan at Belur Math, where his body was kept after his death. The gates of the Math were kept open throughout the night and following day, until the completion of the last rites. The President of India condoled his death.