Of Goan Catholic origin, de Souza was born in the village of Moirá in the Bardes concelho of Portuguese Goa.

He belonged to the fifth vangodd (clan) of the village and is the 12th generation descendant of Shantappa Kamat, a Goud Saraswat Brahmin (GSB) who became Diogo de Souza after his conversion to Christianity in 1618.

He left the priesthood in 1995, with dispensation for laicisation from the Holy See so that he could marry a Portuguese woman named Elvira Correia de Souza.

His work claimed that "Golden Goa" was an expression popularised by art historians, with reference to the baroque church architecture of the early centuries of the Portuguese rule.

[3] The Lusophone University of Lisbon awarded him its Gold Medal of Merit on the same occasion, in recognition of his research, teaching, and critical appreciation and promotion of Lusophony.

[9] A firm believer in the power of web since the early 70s, and a defender of digitalization of historical sources, he founded, in partnership with the Goa-based journalist Frederick Noronha, the Goa-Research-Net in 1997,[10] initially hosted in the Goanet server, and since 2005 on Yahoo!

Since November 2008, Teotónio R. de Souza has continually been a columnist to the Goan daily Herald, in a section which seeks to link Goa and Portugal, in the past and present.