Desai initially intended to become a lawyer but was influenced by labour union activists M. N. Joshi and Thakkar Basha, who motivated him to contribute to the labour movement. He later became an associate to S. M. Joshi, reviewing the social issues that caused problems toward labourers. In this regard, he joined the Servants of India Society which was an organisation that was founded by Gopal Krishna Gokhale. The membership to this organisation was very stringent and the members were admitted only on an oath that they would serve the country without "expecting anything in return". His initiation to social activism was when he had to fight for the rights of the dock workers in Mumbai who were mainly Konkani people. Later, he also went to the Bijapur and Dharwad districts of Karnataka to assist in providing relief when a severe drought had set into those regions. He grew in stature and also held a position in the Mumbai City Corporation.