The 1891 Census lists him as an Artist, born in Headingley, The West Riding of Yorkshire and living at Blue Bell House, St Ives. Tovey sums up his Leeds background as the son of a wine merchant, whilst William was a financially embarassed woollen merchant whose father bailed him out with an annuity, allowing him to take up art instead. He leased the Blue Bell Studio and its yard in St Ives, only to find himself in disputes with locals over rights of way and fencing, etc. His work in art appears to be unregarded and unrecorded, though he belonged to the Arts Club for some period, and was Secretary of the Parish Church Club. He took an active part in the 1892-93 Carnival Masquerades in the town.

Hebblethwaite's prime gift to the St Ives Community appears to be in the way of helping to change attitudes toward not only women's rights, but also and even more strongly to animal welfare (see Tovey, pp340-1). His particular objectives were to prevent the wanton cruelty 'that was often inflicted upon birds and animals by the locals, especially by the children of the fisherfolk' who amused themselves by shooting gulls along the cliff and harbour. The setting of baited hooks, and the maiming of birds that followed this practice was appalling to him, and the RSPCA action in 1917 brought about a cessation of the practice. He also supported action to summon boys for cruelty to ponies and donkeys.

'Hebblethwaite was very much ahead of his time on this issue, and Hudson [W H Hudson, The Land's End] indicated that he found at least twenty people to tell him Hebblethwaite's story and to praise the beneficial impact that he had eventually had.' (Tovey, p341)