Although his father was in the potato trade, Webster was initially employed as a stained glass designer in Lancaster before becoming a dealer in ethnographic antiquities in the 1890s.
[3] William died from alcoholism in Effingham in 1913 and is reportedly buried at Kensal Green Cemetery.
[4] He formed a partnership with his brother Robert Burrow Webster and carried on business as W.D.
[7] In 1904 he sold a significant portion of his collection in a five-day auction in London but continued to trade until his death.
His business records were acquired by the Museum of New Zealand Te Papa Tongarewa, possibly as part of the New Zealand government purchase of the W. O. Oldman collection in 1948[8] or possibly via the work of Kenneth Athol Webster.