On retirement he helped to develop Sri Chaitanya College at Habra in West Bengal. He presided over the All India Brahmo Conference held in 1957. Banerjee was nominated president of the 56th session of the Indian Science Congress to be held at Mumbai in 1969 but he died prematurely on 31 May 1968. He used to deliver lectures on astronomy. He spoke on "Stellar Evolution" at the Allahabad session of the Indian Academy of Sciences in 1946. The road in front of his house in Allahabad was named after him. He had married Probha, daughter of Braja Kumar and Chanchala Niyogi of Hazaribagh in 1920. She was actively involved in social welfare activities, was a commissioner of Allahabad municipality and was a woman magistrate, who held court at home. His elder son Kalyan Banerji died prematurely on 4 June 1975 when he was deputy managing director of State Bank of India. His daughter, Arati, was married to N.R.Dutt, a successful business manager in the steel industry. She died on 9 July 2010. Milon Banerji, Attorney General of India, was his younger son who died on 16 July 2010. His grandson, Pradeep Banerji – son of Kalyan Banerji – graduated from Columbia University, New York, and is presently based in London as a successful professional in the IT industry. His grandson, Debal Banerji – son of Milon Banerji – is a senior lawyer practising in Calcutta High Court and the Supreme Court. His grandson, Gourab Banerji – the younger son of Milon Banerji – was the Additional Solicitor General of India.