He attended Cyfarthfa Grammar School, set within Cyfarthfa Castle, the former mansion of iron-master family the Crawshays. He later attended Newport College of Art, the West Of England College Of Art, Cardiff College of Art and the Academy of Fine Arts, Munich. In 1996 he also became Artist in Residence at Florida International University before teaching on the Master of Fine Arts course in Visual Arts.
Born Geoffrey Robert Olsen in Merthyr Tydfil on 4 November 1943. From 1993 Olsen became the Principal Lecturer in Visual Arts at Oxford Brookes University, becoming Senior Lecturer in Fine Art in 1997 - 2001. From 1999-2000 he was artist in residence at Cheltenham Art Gallery & Museum.
He was diagnosed with leukaemia in 2003, but continued to paint.
He died in Gloucester 6 December 2007. Olsen exhibited widely from the 1970s including exhibitions at the Museum of Modern Art, Wales, the National Library of Wales, the British School in Rome and Florida International University.
His work was also included in a number of group exhibitions, including "Painting the Dragon" at the National Museum of Wales, the "Wales Drawing Biennale 2000" at the Glynn Vivian Art Gallery, the 1992 National Eisteddfod of Wales in Aberystwyth, the Museum of Modern Art, Oxford, Ikon Gallery, Camden Arts Centre, the Corcoran Museum of Art and other locations in Europe and the United States of America.
