Manfred Gnadinger's body was found on Saturday, at his home in the Galician fishing village of Camelle.
Locals say the German-born man died of sadness, after the oil which has been leaking from the sunken Prestige tanker since November covered his garden.
The oil also coated his sculptures, made from stones, driftwood, animal skeletons and other elements washed up by the sea.
Shocked
Gnadinger's sculpture garden was a popular tourist attraction for those visiting the Galician coast.
It was signposted in the village as the "Museum of the German", and Gnadinger charged visitors $1 for admission.
The garden was one of the worst hit by the spill.
The path that led to his small hut was so saturated with oil, that the local authorities gave him a pair of Wellington boots to protect his feet - his only other item of clothing was a loin cloth.
His neighbours in Camelle - where he was known as Man - said the shock caused by the disaster had visibly weakened the 66-year-old recluse.
'My world'
When Gnadinger arrived in Camelle in 1962 he wore a suit and tie and used to attend Mass, according to local newspaper El Correo Gallego.
A few years later he began to show interest in ecological issues.
By the end of the decade he had swapped the suit for the loin cloth he would wear until his last days and moved into a piece of land by the port.
"I came here and built this to create my own world. I was looking for a place to be alone," Reuters news agency quoted him as saying.
"This is my world. I don't think like other people."
In his last comments to the media, he asked for his museum to be left untouched - an historical reminder of the oil spill.