Jantjes attended the Michaelis School of Fine Art at the University of Cape Town from 1966 to 1969. He left apartheid South Africa in 1970 on a DAAD scholarship to study at the Hochschule für bildende Künste Hamburg between 1970 and 1972. He was a founding member of the German anti-apartheid movement. He was granted political asylum in Germany in 1973. He worked as a consultant visual campaign director for the United Nations High Commissioner for Refugees from 1978 to 1982. In 1979 he published the South African Colouring Book, which consisted of eleven collaged serigraphs exploring apartheid in the format of a child’s coloring book.
He moved his studio to Wiltshire, England in 1982. In 1986 he was appointed a Senior Lecturer in Fine Art at Chelsea College of Arts, The London Institute. From 1986 to 1990 he was on the council of the Arts Council of Great Britain and was its consultant for the formation of the Institute of New International Visual Art (InIVA). He also served on the advisory board of the Tate Liverpool from 1992 until 1995, and was a trustee of London's Serpentine Gallery from 1995 until 1998.
He became artistic director of the Henie Onstad Kunstsenter, Hovikodden, near Oslo in 1998 and curated one person exhibitions there of Gordon Bennett, Yinka Shonibare, Susan Hiller, Marie-Jo Lafontaine, Shirin Neshat, Marlene Dumas and Carlos Capelan.
In 2004 he joined the National Museum of Art, Architecture and Design, Oslo, as its Senior Consultant for International Contemporary Exhibitions: he curated exhibitions there on Amar Kanwar, Harun Farocki and Nicholas Hlobo. He was also the Project Director of the Visual Century Project on 20th Century and contemporary South African resulting in the publication, Visual Century: South African Art in Context (2011).
He left the National Museum in 2014 and reopened his studio in Oslo in 2015. He continues to paint, moving between Cape Town, England and Oslo.
One man shows of work by Gavin Jantjes include:
Jantjes’ work in is the collections of Tate Britain, London; Victoria and Albert Museum, London; Arts Council Collection; Wolverhampton Art Gallery; Coventry City Museum; National Museum of African Art, Smithsonian Institution, Washington, D.C.
A Fruitful Incoherence: Dialogues with Artists on Internationalism / [ed by Gavin Jantjes in association with Rohini Malik, Steve Bury and Gilane Tawadros] London: INIVA, 1998. ISBN 1899846131 WorldCat no. 39931382
Christine Eyene, "Gavin Jantjes, Freedom Hunters (1976): Subtexts and Intertwined Narratives" in Outi Remes and Pam Skelton (eds.), Conspiracy Dwellings: Surveillance in Contemporary Art. Cambridge Scholars Publishing, 2010. ISBN 9781443819053 WorldCat no. 551122637. Info at: https://web.archive.org/web/20110609232602/http://www.c-s-p.org/flyers/Conspiracy-Dwellings--Surveillance-in-Contemporary-Art1-4438-1905-0.htm Amna Malik, “Conceptualizing ‘Black’ British art through the lens of exile”, in Kobena Mercer, Exiles, Diasporas & Strangers. INIVA, 2008. ISBN 9781899846450 WorldCat no. 602216574
“Gavin Jantjes”, South African History Online, http://www.sahistory.org.za/people/gavin-jantjes-0
"Korabra" Gavin Jantjes short film made by Pogus Caesar for Central Television, UK 1986
Black Artists & Modernism: http://www.blackartistsnodernism.co.uk/dossier/gavin-jantjes/