Upon receipt of her credentials, Dumont started her career as a classroom teacher. In 1962 and 1963, she studied in the United States as a Fulbright scholar and then in 1965, earned a General Certificate of Education from the Teacher's Union Institute. From 1968 to 1970, Dumont attended the University of Miami, graduating with her bachelor's degree in education. Appointed as head teacher at that time, Dumont then moving into administration, serving as education officer and as deputy director of education, before completing her education career after 21 years in 1975. Dumont then began working as the deputy permanent secretary of the Ministry of Works and Utilities in 1975. She continued her own education and enrolled at Nova University in 1976. Dumont graduated with a doctorate in public administration in 1978 and that same year left the Ministry of Works and began working for Roywest Trust Corporation/Nat West International Trust Holdings Limited as a training officer. She remained with Nat West for the next thirteen years, serving as an assistant manager, then personnel manager and group relations manager, before retiring in 1991. In 1992, Dumont was appointed to the Senate as a representative of the Free National Movement. Simultaneously, she was promoted to the cabinet by Prime MinisterHubert Ingraham, to serve as Minister of Health and Environment. She held this post until 1995, when she was moved to the Ministry of Education and Training. That ministry and Dumont's post transitioned to the Ministry of Education in 1997. She retired from the cabinet in 2000, but retained her Senate seat. In 2001, when Sir Orville Turnquest resigned as Governor-General to facilitate his son Tommy Turnquest's run for party leadership the following year, Dumont was selected as his interim replacement on 13 November 2001. She was confirmed as the permanent Governor-General on 1 January 2002, becoming the first woman to hold the post. She resigned from the post on 30 November 2005 and the following day was feted with a farewell ceremony commemorating her fifty-eight years in public service. In 2007, the University of the West Indies conferred an honorary doctor of laws degree upon Dumont. After leaving public service, Dumont wrote her autobiography, Roses to Mount Fitzwilliam and remained active, speaking to public schools and encouraging youth to further their education.