Charlton was born in London. He studied at London University from 1923 to 1927, and then at the Slade School of Fine Arts in 1930, graduating in 1933.Charlton moved to Bristol to begin a teaching career and became head of Cardiff School of Art in 1938. He combined this role with that of official war artist during World War II.
Charlton took part in a number of group exhibitions during his lifetime, mainly in Wales. These included the Royal National Eisteddfod, WAC and the National Library of Wales in Aberystwyth. He also held a series of one-man shows, including at the Welsh Gallery in Abergavenny in 1973.
Following his death in 1984, a memorial show was held by the National Museum of Wales in Cardiff, where some of his works are still on display.
He is best known for his surreal portrayals of landscapes and interiors. The meticulous detail and extremely fine feathery brushwork of his mature work meant that he completed only three or four paintings a year, ensuring that the total number of his works is very small.
Glynn Vivian Art Gallery in Swansea, National Museum of Wales,Tate Britain, Welsh Arts Council, Imperial War Museum, University of Wales Institute of Science and Technology, Newport Museum and Art Gallery, National Library of Wales and Contemporary Art Society for Wales.