Greaves was born in a “tenement yard” on Carmichael Street, Georgetown, Guyana. He studied Art in Guyana with Edward Burrowes in the Working Peoples’ Art Class (1948-61) and from 1963 to 1968 attended University of Newcastle-upon-Tyne in the UK, where he studied painting, majoring in sculpture for the B.A.Hons degree in Fine Art. He also earned a Diploma in Art Teaching. He was a Fulbright Scholar from 1979 to 1980 at Howard University, where he did printmaking and sculpture for the MFA degree.
In Guyana Greaves taught at Sacred Heart Primary, St. Stanislaus College (his old schools), Berbice High School, Queen’s College, from 1971 to 1975, and was the first Head of the Division of Creative Arts at the University of Guyana from 1975 to 1986. He left Guyana in 1987 and has been resident in Barbados since that time.
In Barbados he served on the first art and craft panel designing the syllabus for the Caribbean Examinations Council and has been a part-time tutor at the Barbados Community College. He was elected a Distinguished Honourable Fellow at University of the West Indies Cave Hill Campus in 2003.
As an artist Greaves works mainly in painting, but has also produced sculpture, drawings, prints and pottery. He was awarded the Guyana national honour of the Golden Arrow of Achievement in 1975. He has exhibited at national level, winning several prizes, and has had one-man shows. He represented Guyana twice at the São Paulo Biennial and once at the Medellin Bienniale in Colombia. He has had major exhibitions in the UK (in 1999 his work was shown in the landmark exhibition curated by Gottfried Donkor, The Elders, alongside that of Brother Everald Brown of Jamaica) and elsewhere in Europe, as well as throughout the Caribbean. He won a gold medal for painting in the Barbados entry at the Santo Domingo Bienniale.