The family name of the artist Garstin Cox, was at the time of his birth Cock, but by the time of the birth of his younger sister four years later in the 1890s, she was also identified as Cox.  It appears that Garstin was also named for his father, i.e. William (Census 1901), but his death notice is in the name of 'Garstin Norman Cox' honouring his great admiration for the work of Phil Whiting. 

The son of the amateur artist William COCK, Garstin Cox began his studies at Camborne Art School, then briefly studied with Stanhope FORBES and in St Ives with John Noble BARLOW. It was while he was touring with Barlow in 1910, that his father, was able to secure a studio in St Ives on St Andrews Street, for them both to employ on painting trips to the town from their home in Camborne. They called it the Beach Studio, and added to it the following year by taking a lease on the 'Ocean Wave Studio' next door at No. 6.

His first painting at the RA was The Coming of Spring in 1912 (at the early age of 19), and he also exhibited at the Royal West of England Academy and Guildhall, London.  Later he worked from the Atlantic Studio, the Lizard (1930).  Golden Autumn (1914), an oil on canvas, is part of the fine art collection of the RCM, Truro.

When he married Dorothy Charlotte Caroline Pike in 1920 his name was recorded as William Norman Garstin Cox and the couple had a son, Garstin T Cox, born in 1921.

He died of bronchial pnuemonia and influenza on 28 February, in the 1933 influenza epidemic during which he had been helping to nurse his ailing father. His father survived him, dying in 1939.