He is the founder of the Sugunavardhini movement (1900) and Depressed classes mission (1909) and also the leader and propagandist of Brahmo Samaj (1893) in Kerala.

Gopalan was born at Anjarakkandy, Tellicherry (now Thalassery), as the first son of Ayyathan Chandhan and Kallatt Chirutha Ammal.

He returned to Kerala in 1897 and joined the Calicut Lunatic asylum (now the Kuthiravattom Mental Hospital) as its first Indian superintendent.

Meanwhile, caste and racial discrimination, malicious practices, and social injustices were prevalent in Kerala, and atrocities against women and children were at their peak.

In the year 1900, Gopalan and wife Kausallyaammal initiated the Sugunavardhini Movement and extended his social reform activities.

He established the Lady Chandhawarkar Elementary School at Calicut with the intention to educate girls and the Dalit (Harijan) communities.

He also served as the registrar of Special Marriage act and was given the rank and adored as the honorary Magistrate by the British Indian Government.

In addition to supporting and educating women and the underprivileged, their movement led reforms to oppose idolatry; promote and conduct Misra Vivaham (inter-caste marriages) and Misra Bhojanam (inter-dining); spread women's education; maintain gender equality; eradicate untouchability, caste and racial discrimination; and conduct mass prayers and communion debates.

The Sugunavardhini Movement and Brahmo Samaj were composed mostly of professionals and intellectuals, including Brahmananda Swamisivayogi, Vagbhatananda Guru, and Brahmavadi P. Kunhiraman, all with a more secular approach to reform.

Rabindranath Tagore described Ayyathan Gopalan as the "Raja Ram Mohan Roy of Kerala" during the annual general conference of the Brahmo Samaj.

On 4 June 1917, Gopalan was honoured by the British Government with the highest civilian award and title, Rao Sahib,[14][15][16][17][18][19] for his social and humanitarian services.

Gopalan translated the Bible of Brahmo Samaj, Brahmodharma,[37][38] which was initially written in Bengali by Maharshi Debendranath Tagore, to Malayalam in 1904.