Domingos de Oliveira Marques was born 20 January 1949 in Ribeiro, Murtosa, the son of Francisco Marques and Augusta da Purificacao Oliveira.
His father was a cod fisher who had visited Saint John's Newfoundland while fishing the Grand Banks and Greenland. He attempted to immigrate in 1953 but was rejected due to his large family. The family eventually succeeded in 1957 when Marques' parents and siblings emigrated while he remained in Portugal in the seminary school at Aveiro. Domingos visited with his family in the summer of 1967. After graduating in 1968 and starting theological studies in Lisbon, Marques, having doubts about his future as a Catholic priest, returned to his family in Toronto in 1968. He worked in the tomato harvest in Chatham to repay his parents the cost of his travels. He worked several jobs, including as a journalist with "O Jornal Português" and in the Promotions Department of the Toronto Star before quitting to pursue a university degree full-time.
As a community activist, Marques was involved during the 1960s in the cultural and theatrical projects of the youth organization of the local St. Mary's Catholic parish and the cable 10 television program Luso-Brasileiro. In the 1970s he reported and edited the community newspaper "Comunidade." Marques taught Portuguese at the First Portuguese Community School at Harbord Collegiate Institute, as well as coordinating projects for the Portuguese Community from the West End YMCA. He edited and researched a book on the history Portuguese immigration to Canada with João Medeiros "Emigrantes Portugueses: 25 anos no Canadá", which was published in 1978.
In the late nineteen-seventies, Marques was self-employed and ran Marquis Printing and Publishing. In 1981, he joined the Workers Compensation Board as a Vocational Rehabilitation Counselor, serving fifteen years in this role. In 1992 he published with Manuela Marujo "With hardened hands : a pictorial history of Portuguese immigration to Canada in the 1950s", a more official history of Portuguese Immigration to Canada.
A volunteer for the Canadian Association of Retired Persons (CARP) and the Portuguese Interagency Network (PIN) in the 1980s, Marques was elected Trustee of the Separate School Board Ward 3-4 in 1991. He is married to Manuela Marujo.