De Soysa married Francesca Coorey, daughter of Mututantrige Bastian Cooray and Kurukulasuriya Senadige Justina Pieris in 1833.

[10][21] Meanwhile, de Soysa also became famous as Babasingha Vedamahatmaya, a sought-after Ayurvedic physician in Kandy and was reputed to have saved the lives of numerous plantation Tamils.

[8][15][22][23] De Soysa's business prospered and he received several government supply contracts, including one that involved in the construction of the Colombo-Kandy road.

[6][15][24] In 1836 de Soysa bid for the Diyatalawa kanda 'Kings Garden-Rajmal Uyana' in Hanguranketha (against British planters such as George Bird) at the request of the administrative officer of the region that had been appointed by king Sri Vikrama Rajasinha.

He had a network of roads built and supplemented the village infrastructure by building reservoirs for irrigating paddy fields and chena cultivations.

[8][31] As a result of the medical and financial assistance given to the landslide victims of Kadugannawa, de Soysa's caravans were safeguarded by Saradiel, the Robin Hood of Ceylon.

[8][15] De Soysa had also met Puran Appu, a hero of the Matale Rebellion, who had on occasion disguised himself as a carter in spying missions to Kandy.

[34] He empowered the traditional Gam Sabhas, established a Legal Aid Society, a library and an association for social reform (Sadarana Sarana Samagama) in Moratuwa.

[14] On 27 December 1860, the Holy Emmanuel Church was consecrated by Dr. James Chapman, the first Bishop of Colombo and the event was attended by the Governor Charles Justin MacCarthy.

[9][17] His brother Mudaliyer Susew de Soysa (1809-1881) gifted an estate opposite the Mount Lavinia Hotel for its maintenance and a part of it was later transferred to relocate S. Thomas' College.

[9][17] De Soysa, often referred to as a father of private enterprise was the pioneer native entrepreneur, philanthropist and social reformer who played the role of a path-finder.

His infrastructure and tank building projects were commendable, considering the fact that it came after the abolition of the traditional rajakriya system of free compulsory labour and the devastation caused following the Kandyan convention.